$NH_{4}Cl$ is acidic due to

When solid potassium cyanide $(KCN)$ is added to water,then:

Which of the following salts when dissolved in water will get hydrolysed?

Which among the following salts forms a basic solution when dissolved in water?

The degree of hydrolysis of a $0.1 \ M$ solution of $ArNH_3^+ Cl^-$ is $0.01$. Find the degree of hydrolysis in a $0.4 \ M$ solution of $ArNH_3^+ Cl^-$.

In which of the following salts,only cationic hydrolysis is involved?