Calculate the exact pH of a aqueous solution of ammonium chloride () at . Given that the of ammonia — Ionic Equilibrium Chemistry Question

💡 Solution & Explanation

$NH_4Cl$ is a salt derived from a strong acid ($HCl$) and a weak base ($NH_3$). It undergoes cationic hydrolysis, creating an acidic solution. The formula is $pH = 7 - \frac{1}{2}pK_b - \frac{1}{2}\log C$. Substituting the given values: $pH = 7 - \frac{1}{2}(5.0) - \frac{1}{2}\log(10^{-2}) = 7 - 2.5 - \frac{1}{2}(-2) = 7 - 2.5 + 1.0 = 5.5$.