State the nature of aqueous solutions containing the following ions with reason: `NH_(4)^(+),F^(-),Cl^(-)`.

Explanation

`NH_(4)^(+):NH_(4)^(+)` ions is the conjugate acid of weak base, `NH_(3)`. In aqueous solution, `NH_(4)^(+)` is stronger than `H_(2)O` [weak bronsted acid]. Hence, in aqueous solution. `NH_(4)^(+)` ion reacts with water to produce `H_(3)O^(+)` ions, leaving the solution acidic.
`NH_(4)(aq)+H_(2)O(l) hArr NH_(3)(aq)+H_(3)O^(+)(aq)`.
`F^(-):F^(-)` ion is the conjugate base of the weak acid. HF, `F^(-)` is stronger than `H_(2)O` [weak Bronsted base] is aqueous solution. for this reason, in aqueous solution, `F^(-)` ion reacts with water to give `OH^(-)` ions, and as a result the solution becomes basic in nature. `F^(-)(aq)+H_(2)O(l)hArr HF(aq)+OH^(-)(aq)`
`Cl^(-):Cl^(-)` is the conjugate base of strong acid, HCl. hence, it is very weak annd cannot react with water. consequently, the aqueous solution of `Cl^(-)` is neutral.