(2) (4 pts) gaseous nitrogen dioxide disproportionates spontaneously into nitric acid and nitrous acid in acidic aqueous solution. show this by writing the balanced chemical reaction and evaluating the standard emf (in v) for the reaction.
(3) (4 pts) nitrous acid will not disproportionate spontaneously to the gases nitrogen dioxide and nitric oxide. show this by writing the balanced chemical reaction and evaluating the standard emf (in v) for the reaction.
(4) (22 pts) gold metal dissolves in aqua regia, which is a mixture of concentrated hydrochloric and concentrated nitric acids, but gold does not dissolve in either acid separately. (you may write net ionic equations in this problem.)
(a) (6 pts) write a balanced chemical equation for the reaction of gold and nitric acid to produce au3+(aq) and nitric oxide. calculate the standard emf (in v) for this reaction. is this reaction spontaneous under standard conditions at 25c?
(b) (6pts)4(aq) and hydrogen gas. calculate the standard emf (in v) for this reaction. is this reaction spontaneous under standard conditions at 25c?
(c) (6pts),i. e.,amixtureofnitricacid and hydrochloric acid, to produce aucl4(aq) and nitric oxide. calculate the standard emf (in v) for the reaction in (e). is this reaction spontaneous under standard conditions at 25c?
(d) (4 pts) concentrated nitric and hydrochloric acid have [h+] > 1.0 m (or [h3o+] > 1.0 m). as [h+] increases, the emf values for the reactions in (a), (b), and (c) all become more positive (or less negative) in value. from this information and your answers to (a), (b), and (c), briefly explain why aqua regia dissolves gold, but that the two separate acids do not.