Question

predict whether aqueous solutions of the following compounds are acidic, basic, or neutral.
compound solution is...?
ki
acidic
basic
neutral
nacn
acidic
basic
neutral
fe(clo4)3
acidic
basic
neutral

Explanation:

• For \(KI\): \(K^{+}\) is the cation of a strong base \(KOH\), and \(I^{-}\) is the anion of a strong acid \(HI\). When \(KI\) dissolves in water, \(K^{+}\) does not hydrolyze (because \(KOH\) is strong) and \(I^{-}\) does not hydrolyze (because \(HI\) is strong). So the solution is neutral.
• For \(NaCN\): \(Na^{+}\) is the cation of a strong base \(NaOH\) (does not hydrolyze). \(CN^{-}\) is the anion of a weak acid \(HCN\). \(CN^{-}+H_{2}O

ightleftharpoons HCN + OH^{-}\), so the solution is basic due to the production of \(OH^{-}\) ions from the hydrolysis of \(CN^{-}\).

• For \(Fe(ClO_{4})_{3}\): \(ClO_{4}^{-}\) is the anion of a strong acid \(HClO_{4}\) (does not hydrolyze). \(Fe^{3 +}\) is a cation that can hydrolyze. \(Fe^{3+}+3H_{2}O

ightleftharpoons Fe(OH)_{3}+3H^{+}\), so the solution is acidic due to the production of \(H^{+}\) ions from the hydrolysis of \(Fe^{3+}\).

Answer:

• \(KI\): neutral
• \(NaCN\): basic
• \(Fe(ClO_{4})_{3}\): acidic