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Define : Cryoscopic constant What is the action of hot/concentrated nitric acid on : (a) Arsenic (b) AntimonyDraw the structure of : (a) Orthophosphoric acid (b) Pyrophosphoric acid |
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Answer» Solution :Cryscopic constant or molal DEPRESSION constant is the depression in frrzing point produced by dissolving 1 mole of solute in 1 kg of solvent . Its units are K kg ` "MOL"^(-1) or .^(@)C "kgmol"^(-1)`or K/molal . (a) When the concentrated nitric acid reacts with the arsenic it forms arsenic acid . ` {:(5 HNO_(3),+,As,rarr,H_(3)AsO_(4),+,5NO_(2),H_(2)O),(("CONC."),,,,("Arsenic acid"),,,):}` (b) When the hot or concentrated nitric acid react with the antimony it forms a COMPOUND named as antimony pentoxide . ` {:(4Sb,+,20HNO_(3),to,Sb_(4)O_(10),+,20NO_(2),+,10H_(2)O),(,,("conc."),,("Antimony oxide"),,,,):}` ( a) Orthophosphoric Acid `(H_(3)PO_(4))` :  ( b) Pyrophosphoric Acid `(H_(4)P_(2)O_(7)`) : `HO-overset(OH)overset("|")underset("O")underset("||")("P ")-O-overset(OH)overset("|")underset("O")underset("||")("P ")-OH` |
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