Saved Bookmarks
| 1. |
Following are explain by reasons : The solution of weak acid-weak base salts is almost neutral. |
|
Answer» Solution :The solution of AMMONIUM cynate is neutral . Ammonium cynate being a salt of weak base `NH_4OH` and weak acid `CH_3COOH` . It undergo dissociated in water to give ammonium ion and acetate ion. `NH_4COOCH_(3(aq)) to NH_(4(aq))^(+) + CH_3COO_((aq))^(-)` The produced positive and negative ions hydrolysis with water. `CH_3COO_((aq))^(-) + NH_(4(aq))^(+) + H_2OhArr CH_3COOH_((aq)) + NH_4OH_((aq))` `CH_3COOH` and `NH_4OH` , ALSO remain into partially dissociated FORM : `CH_3COOH_((aq)) hArr CH_3COO_((aq))^(-) + H_((aq))` `NH_4OH_((aq)) hArr NH_(4(aq))^(+) + OH_((aq))^(-)` `H_((aq))^(+) + OH_((aq))^(-) hArr H_2O_((l))` Thus , the EXTEND of `[H^+]` and `[OH^-]` depends on nature of weak acid and weak base. If `[H^+] = [OH^-]` , So this solution is neutral. `therefore pH=7 + 1/2 (pK_a - pK_b)` Similarly , to understand every weak base and weak acid salts solution are neutral. |
|