{"id":35436,"date":"2022-09-14T09:54:01","date_gmt":"2022-09-14T04:24:01","guid":{"rendered":"https:\/\/apboardsolutions.guru\/?p=35436"},"modified":"2022-09-14T09:54:01","modified_gmt":"2022-09-14T04:24:01","slug":"ap-inter-1st-year-chemistry-study-material-chapter-10","status":"publish","type":"post","link":"https:\/\/apboardsolutions.guru\/ap-inter-1st-year-chemistry-study-material-chapter-10\/","title":{"rendered":"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements &#8211; Group 13"},"content":{"rendered":"<p>Andhra Pradesh BIEAP <a href=\"https:\/\/apboardsolutions.guru\/ap-inter-1st-year-chemistry-study-material\/\">AP Inter 1st Year Chemistry Study Material<\/a> 10th Lesson The p-Block Elements &#8211; Group 13 Textbook Questions and Answers.<\/p>\n<h2>AP Inter 1st Year Chemistry Study Material 10th Lesson The p-Block Elements &#8211; Group 13<\/h2>\n<p><span style=\"color: #0000ff;\">Very Short Answer Questions<\/span><\/p>\n<p>Question 1.<br \/>\nDiscuss the pattern of variation in the oxidation states of Boron to Thallium.<br \/>\nAnswer:<\/p>\n<ul>\n<li>Boron exhibits &#8211; 3 oxidation state due to its small size and non-metalic nature.<\/li>\n<li>Aluminium exhibits +3 oxidation state.<\/li>\n<li>Gallium, Indium and Thallium exhibits both +1 and +3 oxidation states.<\/li>\n<li>In Thallium +1 oxidation state is more stable than +3 due to inert pair effect.<\/li>\n<\/ul>\n<p>Question 2.<br \/>\nHow do you explain higher stability of TlCl<sub>3<\/sub> ?<br \/>\nAnswer:<br \/>\n[TlCl<sub>3<\/sub> is not stable because Tl doesnot exist in Tl<sup>3<\/sup> stable state.] [TlCl is stable because of inertpair effect Tl<sup>+1<\/sup> is stable].<\/p>\n<p><img loading=\"lazy\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/07\/AP-Board-Solutions.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13\" width=\"196\" height=\"17\" \/><\/p>\n<p>Question 3.<br \/>\nWhy does BF<sub>3<\/sub> behave as a Lewis acid ?<br \/>\nAnswer:<br \/>\nBF<sub>3<\/sub> is a electron deficient molecule. It has the tendency to accept an electron pair. Electron pair acceptors are Lewis acids. Hence BF<sub>3<\/sub> behave as a Lewis acid.<\/p>\n<p>Question 4.<br \/>\nIs boric acid a protic acid ? Explain.<br \/>\nAnswer:<br \/>\nBoric acid is a weak mono basic acid. In Boric acid plannar BO<sub>3<\/sub> units are joined by hydrogen bonds. It has layer structure (polymeric). Hence it is not a protic acid. It does not give up a proton.<\/p>\n<p>Question 5.<br \/>\nWhat happens when boric acid is heated ?<br \/>\nAnswer:<br \/>\nBoric acid when heated above 370 K forms meta boric acid. This on heating forms Boric oxide.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24637\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-1.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 1\" width=\"266\" height=\"40\" \/><\/p>\n<p>Question 6.<br \/>\nDescribe the shapes of BF<sub>3<\/sub> and BH<sub>4<\/sub><sup>&#8211;<\/sup>. Assign the hybridization of boron in these species.<br \/>\nAnswer:<\/p>\n<ul>\n<li>Shape of BF<sub>3<\/sub> molecule is Trigonal planar<br \/>\nHybridisation of &#8216;B&#8217; in BF<sub>3<\/sub> is sp<sup>2<\/sup><\/li>\n<li>Shape of BH<sub>4<\/sub><sup>&#8211;<\/sup> molecule is Tetrahedral<br \/>\nHybridisation of &#8216;B&#8217; in BH<sub>4<\/sub><sup>&#8211;<\/sup> is sp<sup>3<\/sup><\/li>\n<\/ul>\n<p><img loading=\"lazy\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/07\/AP-Board-Solutions.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13\" width=\"196\" height=\"17\" \/><\/p>\n<p>Question 7.<br \/>\nExplain why atomic radius of Ga is less than that of &#8216;Al&#8217;.<br \/>\nAnswer:<br \/>\nIn Gallium penultimate shell contains 10-d electrons. Due to this 10-d electrons shielding effect becomes poor on outer most electrons. So nuclear charge increased in Gallium. Hence atomic radius of Ga is lessthan that of &#8216;Al&#8217;.<\/p>\n<p>Question 8.<br \/>\nExplain inert pair effect.<br \/>\nAnswer:<br \/>\nThe reluctance of &#8216;ns&#8217; pair of electrons to take part in bond formation is called inert pair effect.<br \/>\n(or)<br \/>\nThe occurrence of oxidation states two unit lessthan the group oxidation states is called inert pair effect.<br \/>\nEg : In Group &#8211; 13 Tl exhibits +1 oxidation state instead of +3 oxidation state due to inert pair effect.<\/p>\n<p>Question 9.<br \/>\nWrite balanced equations for<br \/>\na) BF<sub>3<\/sub> + LiH \u2192<br \/>\nb) B<sub>2<\/sub>H<sub>6<\/sub> + H<sub>2<\/sub>O \u2192<br \/>\nc) NaH + B<sub>2<\/sub>H<sub>6<\/sub> \u2192<br \/>\nd) H<sub>3<\/sub>BO<sub>3<\/sub> <img loading=\"lazy\" class=\"alignnone size-full wp-image-24638\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-2.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 2\" width=\"54\" height=\"20\" \/><br \/>\ne) B<sub>2<\/sub>H<sub>6<\/sub> + NH<sub>3<\/sub> <img loading=\"lazy\" class=\"alignnone size-full wp-image-24638\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-2.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 2\" width=\"54\" height=\"20\" \/><br \/>\nAnswer:<br \/>\na) 2BF<sub>3<\/sub> + 6LiH \u2192 B<sub>2<\/sub>H<sub>6<\/sub> + 6 LiF<br \/>\nb) B<sub>2<\/sub>H<sub>6<\/sub> + 6H<sub>2<\/sub>O \u2192 2B(OH)<sub>3<\/sub> + 6H<sub>2<\/sub><br \/>\nc) B<sub>2<\/sub>H<sub>6<\/sub> + 2NaH \u2192 2NaBH<sub>4<\/sub><br \/>\nd) H<sub>3<\/sub>BO<sub>3<\/sub> <img loading=\"lazy\" class=\"alignnone size-full wp-image-24638\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-2.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 2\" width=\"54\" height=\"20\" \/> HBO<sub>2<\/sub> <img loading=\"lazy\" class=\"alignnone size-full wp-image-24638\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-2.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 2\" width=\"54\" height=\"20\" \/> B<sub>2<\/sub>O<sub>3<\/sub><br \/>\ne) B<sub>2<\/sub>H<sub>6<\/sub> + 6NH<sub>3<\/sub> \u2192 3[BH<sub>2<\/sub>(NH<sub>3<\/sub>)<sub>2<\/sub>]<sup>+<\/sup> (BH<sub>4<\/sub>)<sup>&#8211;<\/sup> <img loading=\"lazy\" class=\"alignnone size-full wp-image-24639\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-3.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 3\" width=\"64\" height=\"24\" \/> 2B<sub>3<\/sub>N<sub>3<\/sub>H<sub>6<\/sub> + 12H<sub>2<\/sub><\/p>\n<p>Question 10.<br \/>\nWhy is boric acid polymeric ?<br \/>\nAnswer:<br \/>\nBoric acid has layer like lattice. In this structure planar BO<sub>3<\/sub> units are joined by hydrogen bonds and forms a polymeric structure.<\/p>\n<p><img loading=\"lazy\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/07\/AP-Board-Solutions.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13\" width=\"196\" height=\"17\" \/><\/p>\n<p>Question 11.<br \/>\nWhat is the hybridization of B in diborane and borazine ?<br \/>\nAnswer:<\/p>\n<ul>\n<li>In diborane &#8216;B&#8217; hybridisation is sp<sup>3<\/sup><\/li>\n<li>In Borazine &#8216;B&#8217; hybridisation is sp<sup>2<\/sup><\/li>\n<\/ul>\n<p>Question 12.<br \/>\nWrite the electronic configuration of group &#8211; 13 elements.<br \/>\nAnswer:<br \/>\nGeneral outer electronic configuration of Group &#8211; 13 elements is ns<sup>2<\/sup>np<sup>1<\/sup><\/p>\n<ul>\n<li>B &#8211; 1s<sup>2<\/sup>2s<sup>2<\/sup>2p<sup>1<\/sup><\/li>\n<li>Al &#8211; [Ne] 3s<sup>2<\/sup>3p<sup>1<\/sup><\/li>\n<li>Ga &#8211; [Ar] 3d<sup>10<\/sup>4s<sup>2<\/sup>4p<sup>1<\/sup><\/li>\n<li>In &#8211; [Kr] 4d<sup>10<\/sup>5s<sup>2<\/sup>5p<sup>1<\/sup><\/li>\n<li>Tl &#8211; [Xe] 5d<sup>10<\/sup> 6s<sup>2<\/sup>6p<sup>1<\/sup><\/li>\n<\/ul>\n<p>Question 13.<br \/>\nGive the formula of borazine. What is its common name ?<br \/>\nAnswer:<\/p>\n<ul>\n<li>The formula of borazine is B<sub>3<\/sub>N<sub>3<\/sub>H<sub>6<\/sub>.<\/li>\n<li>It&#8217;s common name is &#8220;In organic benzene&#8221; because it is &#8211; iso structural with benzene.<\/li>\n<\/ul>\n<p>Question 14.<br \/>\nGive the formulae of<br \/>\na) Borax<br \/>\nb) Colemanite.<br \/>\nAnswer:<br \/>\na) Formula of Borax is Na<sub>2<\/sub>B<sub>4<\/sub>O<sub>7<\/sub>. 10H<sub>2<\/sub>O<br \/>\nb) Formula of Colemanite is Ca<sub>2<\/sub>B<sub>6<\/sub>O<sub>11<\/sub>.5H<sub>2<\/sub>O<\/p>\n<p><img loading=\"lazy\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/07\/AP-Board-Solutions.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13\" width=\"196\" height=\"17\" \/><\/p>\n<p>Question 15.<br \/>\nGive two uses of aluminium.<br \/>\nAnswer:<br \/>\nUses of Aluminium :<\/p>\n<ul>\n<li>Aluminium is used in packing.<\/li>\n<li>Aluminium is used in utensil making.<\/li>\n<li>Aluminium alloys are used in shaping of pipes, tubes, wires etc.<\/li>\n<li>Aluminium alloys are used in making air craft bodies.<\/li>\n<\/ul>\n<p>Question 16.<br \/>\nWhat happens when<br \/>\na) LiAlH<sub>4<\/sub> and BCl<sub>3<\/sub> mixture in dry ether is warmed and<br \/>\nb) Borax is heated with H<sub>2<\/sub>SO<sub>4<\/sub> ?<br \/>\nAnswer:<br \/>\na) When LiAlH<sub>4<\/sub> and BCl<sub>3<\/sub> mixture is warmed in dry ether diborane is formed.<br \/>\n4BF<sub>3<\/sub> + 3 LiAlH<sub>4<\/sub> \u2192 2B<sub>2<\/sub>H<sub>6<\/sub> + 3 LiF + 3 AlF<sub>3<\/sub><br \/>\nb) Borax is heated with H2S04 then boric acid is formed<br \/>\nNa<sub>2<\/sub>B<sub>4<\/sub>O<sub>7<\/sub> + H<sub>2<\/sub>SO<sub>4<\/sub> + 5H<sub>2<\/sub>O \u2192 Na<sub>2<\/sub>SO<sub>4<\/sub> + 4H<sub>3<\/sub>BO<sub>3<\/sub><\/p>\n<p>Question 17.<br \/>\nSketch the structure of Orthoboric acid.<br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24640\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-4.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 4\" width=\"395\" height=\"326\" \/><\/p>\n<p>Question 18.<br \/>\nWrite the structure of AlCl<sub>3<\/sub> as a climer.<br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24641\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-5.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 5\" width=\"355\" height=\"150\" \/><\/p>\n<p><img loading=\"lazy\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/07\/AP-Board-Solutions.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13\" width=\"196\" height=\"17\" \/><\/p>\n<p>Question 19.<br \/>\nMetal borides (having <sup>10<\/sup>B) are used as protective shield &#8211; Why ?<br \/>\nAnswer:<br \/>\nBoron &#8211; 10 (<sup>10<\/sup>B) has the capacity to absorb neutrons. Hence metal borides (having <sup>10<\/sup>B) are used as protective shields in nuclear industry.<\/p>\n<p><span style=\"color: #0000ff;\">Short Answer Questions<\/span><\/p>\n<p>Question 1.<br \/>\nWrite reactions to justify amphoteric nature of aluminium.<br \/>\nAnswer:<\/p>\n<ul>\n<li>Amphoteric nature means having acidic as well as basic nature.<\/li>\n<li>Aluminium reacts with both mineral acids as well as aqueous alkalis.<\/li>\n<\/ul>\n<p>a) Reaction with mineral acid :<br \/>\n&#8216;Al&#8217; reacts with dil.HCl and liberates hydrogen gas.<br \/>\n2Al + 6HCl \u2192 2AlCl<sub>3<\/sub> + 3H<sub>2<\/sub> \u2191<\/p>\n<p>b) Reaction with aqueous alkali :<br \/>\n&#8216;Al&#8217; reacts with aqueous alkali (NaOH) and liberates hydrogen gas.<br \/>\n2Al + 2NaOH + 6H<sub>2<\/sub>O \u2192 Na<sub>2<\/sub>[Al(OH)<sub>4<\/sub>] + 3H<sub>2<\/sub> \u2191<\/p>\n<p>Question 2.<br \/>\nWhat are electron deficient compounds ? Is BCl<sub>3<\/sub> an electron deficient species ? Explain.<br \/>\nAnswer:<br \/>\nThese are the compounds in which the available no.of valence electrons is lessthan the number required for normal covalent bond formation (or) for writting the Lewis structure of the molecule.<\/p>\n<ul>\n<li>These compounds are electron pair acceptors and acts as Lewis acids.<\/li>\n<li>BCl<sub>3<\/sub> is an electron deficient compound.<\/li>\n<li>In BCl<sub>3<\/sub> &#8216;B&#8217; contains only six electrons instead of eight electrons.<\/li>\n<li>BCl<sub>3<\/sub> has the tendency to accept an electron pair and acts as Lewis acid.<br \/>\nEg : Formation of BCl<sub>3<\/sub> . NH<sub>3<\/sub> :-<br \/>\nBCl<sub>3<\/sub> accepts an electron pair from NH<sub>3<\/sub> and forms the compound BCl<sub>3<\/sub>.NH<sub>3<\/sub> (Tetrahedral)<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24642\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-6.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 6\" width=\"393\" height=\"124\" \/><\/li>\n<\/ul>\n<p><img loading=\"lazy\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/07\/AP-Board-Solutions.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13\" width=\"196\" height=\"17\" \/><\/p>\n<p>Question 3.<br \/>\nSuggest reasons why the B &#8211; F bond lengths in BF<sub>3<\/sub> (130 pm) and BF<sub>4<\/sub><sup>&#8211;<\/sup>\u00a0(143 pm) differ.<br \/>\nAnswer:<br \/>\nAbout BF<sub>3<\/sub> :<\/p>\n<ul>\n<li>In BF<sub>3<\/sub> the central atom &#8216;B&#8217; contains three bond pairs in the valency shell.<\/li>\n<li>&#8216;B&#8217; under goes sp<sup>2<\/sup> hybridisation.<\/li>\n<li>Shape of the molecule is trigonal planar.<\/li>\n<\/ul>\n<p>About BF<sub>4<\/sub><sup>&#8211;<\/sup> :<\/p>\n<ul>\n<li>In BF<sub>4<\/sub><sup>&#8211;<\/sup> the central atom &#8216;B&#8217; contains four bond pairs in the valency shell.<\/li>\n<li>&#8216;B&#8217; under goes sp<sup>3<\/sup> hybridisation.<\/li>\n<li>Shape of the molecule is tetrahedral.<\/li>\n<li>The above reasons suggent that the difference in bond lengths of BF<sub>3<\/sub> (130 pm) and BF<sub>4<\/sub><sup>&#8211;<\/sup> (143 pm).<\/li>\n<\/ul>\n<p>Question 4.<br \/>\nB &#8211; Cl bond has a bond moment. Explain why BCl<sub>3<\/sub> molecule has zero dipolemoment.<br \/>\nAnswer:<\/p>\n<ul>\n<li>B &#8211; Cl bond is a polar bond so it has bond moment.<\/li>\n<li>BCl<sub>3<\/sub> molecule is non-polar because of its symmetrical structure. (Trigonal planar structure)<\/li>\n<li>Symmetrical molecules has zero dipole moment.<br \/>\n\u2234 Dipole moment of BCl<sub>3<\/sub> (\u03bc) = 0<\/li>\n<\/ul>\n<p><img loading=\"lazy\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/07\/AP-Board-Solutions.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13\" width=\"196\" height=\"17\" \/><\/p>\n<p>Question 5.<br \/>\nExplain the structure of boric acid.<br \/>\nAnswer:<\/p>\n<ul>\n<li>Boric acid has a layer lattice.<\/li>\n<li>In this layer lattice planar BO<sub>3<\/sub> units are joined by hydrogen bonds.<\/li>\n<li>The structure of Boric acid is polymeric as shown in following figure.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24643\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-7.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 7\" width=\"353\" height=\"318\" \/><\/li>\n<li>In the above structure dotted lines represents the hydrogen bonds<\/li>\n<\/ul>\n<p>Question 6.<br \/>\nWhat happens when<br \/>\na) Borax is heated strongly<br \/>\nb) Boric acid is added to water<br \/>\nc) Aluminium is heated with dilute NaOH<br \/>\nd) BF<sub>3<\/sub> is treated with ammonia<br \/>\ne) Hydrated alumina is treated with aq.NaOH solution.<br \/>\nAnswer:<br \/>\na) Borax on heating first loses water molecules and forms sodium tetraborate. This on further heating forms a mixture of sodium metaborate and boric an hydride. This mixture is solidifies into glass like substance.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24644\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-8.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 8\" width=\"444\" height=\"77\" \/><\/p>\n<p>b) Boric acid is added to water, boric acid accepts a hydroxyl ion from water.<br \/>\nB(OH)<sub>3<\/sub> + 2H<sub>2<\/sub>O \u2192 [B(OH)<sub>4<\/sub>]<sup>&#8211;<\/sup> + H<sub>3<\/sub>O<sup>+<\/sup><\/p>\n<p>c) Aluminium is heated with dilute NaOH, sodium metaluminate is formed with the liberation of hydrogen gas.<br \/>\n2Al + 2NaOH \u2192 2NaAlO<sub>2<\/sub> + H<sub>2<\/sub> \u2191<\/p>\n<p>d) BF<sub>3<\/sub> is treated with NH<sub>3<\/sub> an addition compound BF<sub>3<\/sub>. NH<sub>3<\/sub> is formed. BF<sub>3<\/sub> accepts an electron pair from NH3 and forms a dative bond.<br \/>\nBF<sub>3<\/sub> + <img loading=\"lazy\" class=\"alignnone size-full wp-image-24645\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-9.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 9\" width=\"34\" height=\"27\" \/> \u2192 [BF<sub>3<\/sub> \u2190 NH<sub>3<\/sub>] \u2192 [BF<sub>3<\/sub>.NH<sub>3<\/sub>]<\/p>\n<p>e) Hydrated Alumina is treated with aq.NaOH to form sodium metaluminate.<br \/>\nAl<sub>2<\/sub>O<sub>3<\/sub>.2H<sub>2<\/sub>O + 2NaOH<sub>(aq)<\/sub> \u2192 2NaAlO<sub>(aq)<\/sub> + 3H<sub>2<\/sub>O<\/p>\n<p>Question 7.<br \/>\nGive reasons<br \/>\na) Conc.HNO<sub>3<\/sub> can be transported in aluminium container.<br \/>\nb) A mixture of dil. NaOH and aluminium pieces is used to open drain.<br \/>\nc) Aluminium alloys are used to make aircraft body.<br \/>\nd) Aluminium utensils should not be kept in water overnight.<br \/>\ne) Aluminium wire is used to make transmission cables.<br \/>\nAnswer:<br \/>\na) Cone. HNO<sub>3<\/sub> can be transported in Aluminium containers because Al is passive towards Conc.HNO<sub>3<\/sub> due to the formation of thin layer of Al<sub>2<\/sub>O<sub>3<\/sub> on the surface.<\/p>\n<p>b) A mixture of dil.NaOH and aluminium pieces is used to open drain because it acts as cleaning agent.<br \/>\n2Al + 2NaOH \u2192 2NaAlO<sub>2<\/sub> + H<sub>2<\/sub><\/p>\n<p>c) Aluminium alloys are used to make air craft body because it is a light metal, soft, malleable, ductile and tenacious. It shows resistance to atmosphere corrosion.<\/p>\n<p>d) Aluminium utensils should not be kept in water overnight because Aluminium reacts with water and liberates hydrogen gas and heat. It makes colour dissolving and sometimes Aluminium compounds are toxic in nature.<\/p>\n<p>e) Aluminium wire used to make transmission cables because of it&#8217;s good conductivity (electrical) and resistance to atmospheric corrosion.<\/p>\n<p><img loading=\"lazy\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/07\/AP-Board-Solutions.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13\" width=\"196\" height=\"17\" \/><\/p>\n<p>Question 8.<br \/>\nExplain why the electronegativity of Ga, In and Tl will not vary very much.<br \/>\nAnswer:<\/p>\n<ol>\n<li>Ga, In and Tl have the electro negativity values 1.6, 1.7 and 1.8 respectively.<\/li>\n<li>In Ga, In and Tl the d-electrons (d<sup>10<\/sup>) in penultimate shell do not shield the outer most electrons from nuclear attraction effectively.<\/li>\n<li>The reason for the above fact is.the shielding effect of various electrons in the orbitals follows the order<br \/>\ns &gt; p &gt; d &gt; f.<\/li>\n<li>Hence the outer electrons are held more firmly by the nucleus. Because of this, atoms with d- electrons in the penultimate shell (d<sup>10<\/sup>) are smaller in size. Ga, In and Tl has same number of penultimate shell electrons.<\/li>\n<li>So, Ga, In and Tl will not vary very much in their electronegativities.<\/li>\n<\/ol>\n<p>Question 9.<br \/>\nExplain Borax bead test with a suitable example. [T.S. Mar. 16] [Mar. 13]<br \/>\nAnswer:<br \/>\nBorax bend test: This test is useful in the identification of basic radicals in qualitative analysis. On heating borax swells into a white, opaque mass of anhydrous sodium tetra borate. When it is fused, borax glass is obtained. Borax glass is sodium meta borate and B203. The boric anhydride, B203, combined with metal oxides to form metal metaborates as coloured beads. The reactions are as follows :<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24646\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-10.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 10\" width=\"501\" height=\"195\" \/><\/p>\n<p>Question 10.<br \/>\nExplain the structure of diborane. [A.P. Mar. 16] [A.P. &amp; T.S. Mar. 15]<br \/>\nAnswer:<br \/>\nDiborane is an electron deficient compound. It has &#8217;12&#8217; valency electrons for bonding purpose instead of &#8217;14&#8217; electrons.<\/p>\n<p>In diborane each boron atom undergoes sp3 hybridization out of the four hybrid orbitals one is vacant.<\/p>\n<p>Each boron forms two, \u03c3 &#8211; bonds (2 centred &#8211; 2 electron bonds) bonds with two hydrogen atoms by overlapping with their &#8216;1s&#8217; orbital.<\/p>\n<p>The remaining hybrid orbitals of boran used for the formation of B-H-B bridge bonds.<\/p>\n<p>In the formation of B-H-B bridge, half filled sp3 hybrid ofbital of one boron atom and vacant sp<sup>3<\/sup> hybrid orbital of second boron atom overlap with 1s orbital of H-atom.<\/p>\n<p>These three centred two electron bonds are also called as banana bonds. These bonds are present above and below the plane of BH<sub>2<\/sub> units.<\/p>\n<p>Diborane contains two coplanar BH<sub>2<\/sub> groups. The four hydrogen atoms are called terminal hydrogen atoms and the remaining two hydrogens are called bridge hydrogen atoms.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24647\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-11.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 11\" width=\"717\" height=\"143\" \/><br \/>\nBonding in diborane, Each B atom uses sp<sup>3<\/sup> hybrids for bonding. Out of the four sp<sup>3<\/sup> hybrids on each B atom, one is without an electron shown in broken lines. The terminal B-H bonds are normal 2-centre-2- electron bonds but the two bridge bonds are 3-centre-2- electron bonds. The 3-centre-2-electron bridge bonds are also referred to as banana bonds.<\/p>\n<p><img loading=\"lazy\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/07\/AP-Board-Solutions.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13\" width=\"196\" height=\"17\" \/><\/p>\n<p>Question 11.<br \/>\nExplain the reactions of aluminium with acids.<br \/>\nAnswer:<br \/>\nReactions of &#8216;Al&#8217; with adds :<br \/>\ni) DiS. (or) cone. HCl dissolves Al and gives H<sub>2<\/sub>.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24648\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-12.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 12\" width=\"268\" height=\"53\" \/><\/p>\n<p>ii) a) Dil.H<sub>2<\/sub>SO<sub>4<\/sub> liberates H<sub>2<\/sub>.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24649\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-13.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 13\" width=\"304\" height=\"58\" \/><br \/>\nb) Cone. H<sub>2<\/sub>SO<sub>4<\/sub> dissolves the metal &#8216;Al&#8217; and gives SO<sub>2<\/sub>.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24650\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-14.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 14\" width=\"356\" height=\"50\" \/><\/p>\n<p>iii) a) Very dil.HNO<sub>3<\/sub> is reduced to NH<sub>4<\/sub> NO<sub>3<\/sub> by Al.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24651\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-15.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 14\" width=\"414\" height=\"53\" \/><br \/>\nb) Cone. HNO<sub>3<\/sub> makes &#8216;Al&#8217; passive due to the formation of a thin film of oxide layer on the metal surface.<\/p>\n<p>Question 12.<br \/>\nWrite a short note on the anamalous behaviour of boron in group &#8211; 13.<br \/>\nAnswer:<\/p>\n<ul>\n<li>Among Group &#8211; 13 elements &#8216;B&#8217; is only the non metal.<\/li>\n<li>&#8216;B&#8217; forms only covalents compounds.<\/li>\n<li>&#8216;B&#8217; doesnot displaces hydrogen from acids.<\/li>\n<li>&#8216;B&#8217; shows diagonal relationship with &#8216;Si&#8217;.<\/li>\n<li>&#8216;B&#8217; forms acidic oxide where as other elements of group forms amphoteric oxides and basic oxides.<\/li>\n<li>&#8216;B&#8217; has only two electrons in the penultimate shell.<\/li>\n<li>&#8216;B&#8217; has covalency &#8216;4&#8217; where as other elements has covalency of maximum &#8216;6&#8217;.<\/li>\n<\/ul>\n<p><img loading=\"lazy\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/07\/AP-Board-Solutions.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13\" width=\"196\" height=\"17\" \/><\/p>\n<p>Question 13.<br \/>\nAluminium reacts with dil.HNO<sub>3<\/sub> but not with conc.HNO<sub>3<\/sub> &#8211; explain.<br \/>\nAnswer:<\/p>\n<ul>\n<li>Dilute HNO<sub>3<\/sub> reacts with Aluminium slowly and forms aluminium nitrate and ammonium nitrate.<br \/>\n8Al + 30 HNO<sub>3<\/sub> \u2192 8 Al(NO<sub>3<\/sub>)<sub>3<\/sub> + 3NH<sub>4<\/sub>NO<sub>3<\/sub> + 9H<sub>2<\/sub>O<\/li>\n<li>Aluminium doesnot react with cone. HNO<sub>3<\/sub>.<\/li>\n<\/ul>\n<p>Reasons :<\/p>\n<ul>\n<li>Aluminium is passive towards cone. HNO<sub>3<\/sub> due to the formation of thin film of Al<sub>2<\/sub>O<sub>3<\/sub> layer on the surface.<\/li>\n<li>Because of this passivity between Al and conc.HNO<sub>3<\/sub>, conc.HNO<sub>3<\/sub> is transported in Aluminium containers.<\/li>\n<\/ul>\n<p>Question 14.<br \/>\nGive two methods of preparation of diborane.<br \/>\nAnswer:<\/p>\n<ol>\n<li>In industries diborane is prepared by the reaction between boron tri fluoride and lithium hydride.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24652\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-16.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 16\" width=\"271\" height=\"33\" \/><\/li>\n<li>Boron trichloride and hydrogen mixture subjected to silent electric discharge at low pressure to from diborane.<br \/>\n2BCl<sub>3<\/sub> + 6H<sub>2<\/sub> \u2192 B<sub>2<\/sub>H<sub>6<\/sub> + 6HCl<\/li>\n<li>Boron trichloride undergo reduction with LiAlH<sub>4<\/sub> to form diborane.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24653\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-17.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 17\" width=\"384\" height=\"34\" \/><\/li>\n<\/ol>\n<p>Question 15.<br \/>\nHow does diborane react with<br \/>\na) H<sub>2<\/sub>O<br \/>\nb) CO<br \/>\nc) N(CH<sub>3<\/sub>)<sub>3<\/sub> ?<br \/>\nAnswer:<br \/>\na) Diborane reacts with water to form boric acid and hydrogen.<br \/>\nB<sub>2<\/sub>H<sub>6<\/sub> + 6H<sub>2<\/sub>O \u2192 2H<sub>3<\/sub>BO<sub>3<\/sub> + 6H<sub>2<\/sub>\u2191<\/p>\n<p>b) Diborane reacts with CO at 100\u00b0 C and 20 atm. pressure to form borane carbonyl.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24654\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-18.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 18\" width=\"245\" height=\"46\" \/><br \/>\nc) Diborane reacts with N(CH<sub>3<\/sub>)<sub>3<\/sub> and form a adduct.<br \/>\nB<sub>2<\/sub>H<sub>6<\/sub> + 2N(CH<sub>3<\/sub>)<sub>3<\/sub> \u2192 2BH<sub>3<\/sub>.N(CH<sub>3<\/sub>)<sub>3<\/sub> (adduct)<br \/>\nReactions b, c are cleavage reactions.<\/p>\n<p><img loading=\"lazy\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/07\/AP-Board-Solutions.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13\" width=\"196\" height=\"17\" \/><\/p>\n<p>Question 16.<br \/>\nAl<sub>2<\/sub>O<sub>3<\/sub> is amphoteric &#8211; explain with suitable reactions.<br \/>\nAnswer:<\/p>\n<ul>\n<li>Amphoteric oxides are the oxides which possess both acidic as well as basic nature.<br \/>\nAl<sub>2<\/sub>O<sub>3<\/sub> possess both acidic as well as basic behaviour.<\/li>\n<li>Al<sub>2<\/sub>O<sub>3<\/sub> react with both acids as well as bases to produce salts and water.<br \/>\nSupporting reactions for amphoteric nature of Al<sub>2<\/sub>O<sub>3<\/sub><br \/>\na) With acids:<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24655\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-19.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 19\" width=\"416\" height=\"52\" \/><br \/>\nb) With bases:<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24656\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-20.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 20\" width=\"340\" height=\"52\" \/><\/li>\n<\/ul>\n<p>Question 17.<br \/>\nNa<sub>2<\/sub>B<sub>4<\/sub>O<sub>7<\/sub> + Cone. H<sub>2<\/sub>SO<sub>4<\/sub> \u2192 A <img loading=\"lazy\" class=\"alignnone size-full wp-image-24657\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-21.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 21\" width=\"85\" height=\"43\" \/> &gt; B (Green edged flame) Identify A and B<br \/>\nHint: A = H<sub>3<\/sub>BO<sub>3<\/sub> B = (C<sub>2<\/sub>H<sub>5<\/sub>)<sub>3<\/sub> BO<sub>3<\/sub>.<br \/>\nAnswer:<br \/>\nNa<sub>2<\/sub>B<sub>4<\/sub>O<sub>7<\/sub> + Cone. H<sub>2<\/sub>SO<sub>4<\/sub> + 5H<sub>2<\/sub>O \u2192 4H<sub>3<\/sub>BO<sub>3<\/sub> A) <img loading=\"lazy\" class=\"alignnone size-full wp-image-24657\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-21.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 21\" width=\"85\" height=\"43\" \/> B) 4(C<sub>2<\/sub>H<sub>5<\/sub>)<sub>3<\/sub>BO<sub>3<\/sub><\/p>\n<ul>\n<li>&#8216;A&#8217; is H<sub>3<\/sub>BO<sub>3<\/sub><\/li>\n<li>&#8216;B&#8217; is (C<sub>2<\/sub>H<sub>5<\/sub>)<sub>3<\/sub> BO<sub>3<\/sub>.<\/li>\n<\/ul>\n<p><span style=\"color: #0000ff;\">Long Answer Questions<\/span><\/p>\n<p>Question 1.<br \/>\nHow are borax and boric acid prepared ? Explain the action of heat on them.<br \/>\nAnswer:<br \/>\nPreparation of Borax:<br \/>\nBoric acid on heating first forms tetraboric acid. This on reaction with sodium hydroxide to form borax.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24658\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-22.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 22\" width=\"341\" height=\"41\" \/><br \/>\nPreparation of Boric acid : Borax is treated with conc.H<sub>2<\/sub>SO<sub>4<\/sub> boric acid is formed.<br \/>\nNa<sub>2<\/sub>B<sub>4<\/sub>O<sub>7<\/sub> + H<sub>2<\/sub>SO<sub>4<\/sub> + 5H<sub>2<\/sub>O \u2192 4H<sub>3<\/sub>BO<sub>3<\/sub> + Na<sub>2<\/sub>SO<sub>4<\/sub>.<\/p>\n<p>Heating of Borax :<br \/>\nBorax on heating first loses the water molecules and forms sodium tetraborate. This on further heating forms a mixture of sodium meta borate and boric anhydride.<br \/>\nNa<sub>2<\/sub>B<sub>4<\/sub>O<sub>7<\/sub>.10H<sub>2<\/sub>O <img loading=\"lazy\" class=\"alignnone size-full wp-image-24638\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-2.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 2\" width=\"54\" height=\"20\" \/> Na<sub>2<\/sub>B<sub>4<\/sub>O<sub>7<\/sub> imgg 2 2 NaBO<sub>2<\/sub> + B<sub>2<\/sub>O<sub>3<\/sub>.<\/p>\n<p>Heating of Boric acid :<br \/>\nBoric acid on heating forms boric anhydride. The reaction depends on the temperature used.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24659\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-23.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 23\" width=\"444\" height=\"118\" \/><\/p>\n<p>Question 2.<br \/>\nHow is diborane prepared ? Explain its structure.<br \/>\nAnswer:<br \/>\nIn industries diborane is prepared by the reaction between boran tri fluoride and lithium hydride.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24660\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-24.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 24\" width=\"270\" height=\"28\" \/><br \/>\nBoron trichioride and hydrogen mixture subjected to silent electric discharge at low pressure to from diborane.<br \/>\n2BCl<sub>3<\/sub> + 6H<sub>2<\/sub> \u2192 B<sub>2<\/sub>H<sub>6<\/sub> + 6HCl<br \/>\nBoron trichloride undergo reduction with LiAlH<sub>4<\/sub> to form diborane.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24661\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-25.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 25\" width=\"386\" height=\"29\" \/><br \/>\nDiborane is an electron deficient compound. It has &#8217;12&#8217; valency electrons for bonding purpose instead of &#8217;14&#8217; electrons.<\/p>\n<p>In diborane each boron atom undergoes sp3 hybridization out of the four hybrid orbitals one is vacant.<\/p>\n<p>Each boron forms two, \u03c3 &#8211; bonds (2 centred &#8211; 2 electron bonds) bonds with two hydrogen atoms by overlapping with their &#8216;1s&#8217; orbital.<\/p>\n<p>The remaining hybrid orbitals of boran used for the formation of B-H-B bridge bonds.<\/p>\n<p>In the formation of B-H-B bridge, half filled sp3 hybrid ofbital of one boron atom and vacant sp<sup>3<\/sup> hybrid orbital of second boron atom overlap with 1s orbital of H-atom.<\/p>\n<p>These three centred two electron bonds are also called as banana bonds. These bonds are present above and below the plane of BH<sub>2<\/sub> units.<\/p>\n<p>Diborane contains two coplanar BH<sub>2<\/sub> groups. The four hydrogen atoms are called terminal hydrogen atoms and the remaining two hydrogens are called bridge hydrogen atoms.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24647\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-11.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 11\" width=\"717\" height=\"143\" \/><br \/>\nBonding in diborane, Each B atom uses sp<sup>3<\/sup> hybrids for bonding. Out of the four sp<sup>3<\/sup> hybrids on each B atom, one is without an electron shown in broken lines. The terminal B-H bonds are normal 2-centre-2- electron bonds but the two bridge bonds are 3-centre-2- electron bonds. The 3-centre-2-electron bridge bonds are also referred to as banana bonds.<\/p>\n<p><img loading=\"lazy\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/07\/AP-Board-Solutions.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13\" width=\"196\" height=\"17\" \/><\/p>\n<p>Question 3.<br \/>\nWrite any two methods of preparation of diborane. How does it react with<br \/>\na) Carbon monoxide and<br \/>\nb) Ammonia ?<br \/>\nAnswer:<br \/>\nPreparation of diborane:<br \/>\nIn industries diborane is prepared by the reaction between boroh tri fluoride and lithium hydride.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24660\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-24.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 24\" width=\"270\" height=\"28\" \/><br \/>\nBoron trichloride and hydrogen mixture subjected to silent electric discharge at low pressure to from diborane.<br \/>\n2BCl<sub>3<\/sub> + 6H<sub>2<\/sub> \u2192 B<sub>2<\/sub>H<sub>6<\/sub> + 6HCl<br \/>\nBoron trichloride undergo reduction with LiAlH<sub>4<\/sub> to form diborane.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24661\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-25.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 25\" width=\"386\" height=\"29\" \/><\/p>\n<p>a) Reaction with carbon monoxide :<br \/>\nDiborane reacts with CO at 100\u00b0 C and 20 atm. pressure to form borane carbonyl.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24662\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-26.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 26\" width=\"244\" height=\"45\" \/><\/p>\n<p>b) Reaction with ammonia<br \/>\nDiborane reacts with ammonia at 120\u00b0 C first forms B<sub>2<\/sub>H<sub>6<\/sub>.2NH<sub>3<\/sub> (or) [BH<sub>2<\/sub>(NH<sub>3<\/sub>)<sub>2<\/sub>]<sup>+<\/sup>[BH<sub>4<\/sub>]<sup>&#8211;<\/sup> and on further heating forms borazole (or) borazine. Which is also called as &#8220;In organic benzene&#8221;. It has iso structural with benzene. Flence it is named as &#8220;Inorganic Benzene&#8221;.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24663\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/09\/AP-Inter-1st-Year-Chemistry-Study-Material-Chapter-10-The-p-Block-Elements-Group-13-27.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13 27\" width=\"577\" height=\"71\" \/><\/p>\n<p><span style=\"color: #0000ff;\">Solved Problems<\/span><\/p>\n<p>Question 1.<br \/>\nStandard electrode potential values, E<sup>\u0398<\/sup> for Al<sup>3+<\/sup> \/ Al is &#8211; 1.66 V and that of Tl<sup>3+<\/sup> \/ Tl is + 1.26 V. Predict about the formation of M<sup>3+<\/sup> ion in solution and compare the electropositive character of the two metals.<br \/>\nSolution:<br \/>\nStandard electrode potential values for two half cell reactions suggest that aluminium has high tendency to make Al<sup>3+<\/sup> (aq) ions, whereas Tl<sup>3+<\/sup> is not only unstable in solution but is a powerful oxidising agent also. Thus Tl<sup>+<\/sup> is more stable in solution than Tl<sup>3+<\/sup>. Aluminium being able to form +3 ions easily, is more electropositive than thallium.<\/p>\n<p>Question 2.<br \/>\nWhite fumes appear around the bottle of anhydrous aluminium chloride. Give reason.<br \/>\nSolution:<br \/>\nAnhydrous aluminium chloride is partially hydrolysed with atmospheric moisture to liberate HCl gas. Moist HCl appears white in colour.<\/p>\n<p><img loading=\"lazy\" src=\"https:\/\/apboardsolutions.com\/wp-content\/uploads\/2022\/07\/AP-Board-Solutions.png\" alt=\"AP Inter 1st Year Chemistry Study Material Chapter 10 The p-Block Elements - Group 13\" width=\"196\" height=\"17\" \/><\/p>\n<p>Question 3.<br \/>\nBoron is unable to form \\(\\mathrm{BF}_6^{3-}\\) ion. Explain.<br \/>\nSolution:<br \/>\nDue to non &#8211; availability of d orbitals, boron is unable to expand its octet. Therefore, the maximum covalence of boron cannot exceed 4.<\/p>\n<p>Question 4.<br \/>\nWhy is boric acid considered as a weak acid ?<br \/>\nSolution:<br \/>\nBecause it is not able to release H<sup>+<\/sup> ions on its own. It receives OH<sup>+<\/sup> ions from water molecule to complete its octet and in turn releases H<sup>+<\/sup> ions.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Andhra Pradesh BIEAP AP Inter 1st Year Chemistry Study Material 10th Lesson The p-Block Elements &#8211; Group 13 Textbook Questions and Answers. AP Inter 1st Year Chemistry Study Material 10th Lesson The p-Block Elements &#8211; Group 13 Very Short Answer Questions Question 1. Discuss the pattern of variation in the oxidation states of Boron to &hellip;<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"spay_email":""},"categories":[15],"tags":[],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/apboardsolutions.guru\/wp-json\/wp\/v2\/posts\/35436"}],"collection":[{"href":"https:\/\/apboardsolutions.guru\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/apboardsolutions.guru\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/apboardsolutions.guru\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/apboardsolutions.guru\/wp-json\/wp\/v2\/comments?post=35436"}],"version-history":[{"count":1,"href":"https:\/\/apboardsolutions.guru\/wp-json\/wp\/v2\/posts\/35436\/revisions"}],"predecessor-version":[{"id":35437,"href":"https:\/\/apboardsolutions.guru\/wp-json\/wp\/v2\/posts\/35436\/revisions\/35437"}],"wp:attachment":[{"href":"https:\/\/apboardsolutions.guru\/wp-json\/wp\/v2\/media?parent=35436"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/apboardsolutions.guru\/wp-json\/wp\/v2\/categories?post=35436"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/apboardsolutions.guru\/wp-json\/wp\/v2\/tags?post=35436"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}