Al(CN)3
CH3COOK
FeCl3
Pb(CH3COO)2
CH3COOK + H2O → Hydrolysis → CH3COOH + KOH
FeCl3 + H2O → Hydrolysis → Fe(OH)3 + HCl
Pb(CH3COO)2 + H2O → Hydrolysis → Pb(OH)2 + 2CH3COOH
Al(CN)3 + H2O → Hydrolysis → Al(OH)3 + 3HCN
CH3COOK on hydrolysis gives CH3COOH + KOH. KOH is the strongest base than Fe(OH)3, Pb(OH)2, Al(OH)3. Hence, it is the most basic among all.