Question

Explain with equations and calculations, when necessary, whether an aqueous solution of each of these salts is acidic, basic, or neutral: (a) KBr; (b)NH4I; (c) KCN

Short answer

Answer

(a) Indifferent

(b) Acidic

(c) Fundamental

Step-by-step solution

Explanation of the concept

An acidic salt is an aqueous solution of a salt that contains the anion of the strong acid and the cation of the weak base. The anion of the weak base reacts with water to form the hydronium ion, causing the solution to become acidic. As an example, consider ammonium chloride. A basic salt is an aqueous solution of a salt that contains the cation of the strong base and the anion of the weak acid. The cation of the strong acid reacts with water, resulting in the formation of the hydroxide ion. As a result, the solution is simplified. As an example, consider sodium supplied. A neutral salt is an aqueous solution of a salt containing the cation.

Disintegration of salts into the water

$\left(a\right)\mathit{K}\mathit{B}\mathit{r}$

$\mathit{K}\mathit{B}\mathit{r}$will disintegrate in water

$\mathit{K}\mathit{B}\mathit{r}\mathbf{\to }{\mathit{K}}^{\mathbf{-}}\mathbf{+}\mathit{B}{\mathit{r}}^{\mathbf{-}}$

$K^{+}$is an ion of a strong base $\mathit{K}\mathit{O}\mathit{H}\mathbf{}\mathit{a}\mathit{n}\mathit{d}\mathbf{}\mathit{B}{\mathit{r}}^{\mathbf{-}}$is an ion of a powerful acid $\left(HBr\right)$.

A salt containing both ions from strong acids and bases will produce a neutral solution.

Disintegration of salts into the water

$\left(b\right)\mathit{N}{\mathit{H}}_{\mathbf{4}}\mathit{I}$

$\mathit{N}{\mathit{H}}_{\mathbf{4}}\mathit{I}$Will disintegrate in water

$\mathit{N}{\mathit{H}}_{\mathbf{4}}\mathit{I}\mathbf{\to }\mathit{N}{\mathit{H}}_{\mathbf{4}}^{\mathbf{+}}\mathbf{+}{\mathit{I}}^{\mathbf{-}}$

$\mathit{N}{\mathit{H}}_{\mathbf{4}}^{\mathbf{+}}$is a weak base's ion $\mathbf{\left(}{\mathbf{NH}}_{\mathbf{3}}\mathbf{\right)}\mathit{a}\mathit{n}\mathit{d}{\mathit{I}}^{\mathbf{-}}$is an ion of a powerful acid $\left(HI\right)$An acidic solution is produced by combining salt with a cation of a weak base and an anion of a strong acid.

Disintegration of salts into the water

$\left(c\right)\mathit{K}\mathit{C}\mathit{N}$

$\mathit{K}\mathit{C}\mathit{N}$will disintegrate in water

$\mathit{K}\mathit{C}\mathit{N}\mathbf{\to }{\mathit{K}}^{\mathbf{+}}\mathbf{+}\mathit{C}{\mathit{N}}^{\mathbf{-}}$

${\mathit{K}}^{\mathbf{+}}$is an ion derived from a strong base $\mathbf{\left(}\mathbf{KOH}\mathbf{\right)}\mathbf{}\mathit{a}\mathit{n}\mathit{d}\mathit{C}{\mathit{H}}^{\mathbf{-}}$is a weak acid's ion $\mathbf{\left(}\mathbf{HCN}\mathbf{\right)}$A basic solution is produced by combining salt with a cation of a strong base and an anion of a weak acid.

As a result, all the 3 salts are

1. Indifferent, (b) Acidic, (c) Fundamental.