Answer
(4) - This is the weakest acid.
Work Step by Step
(4) - This is the weakest acid. Sodium hydroxide is a very strong base. Group I and Group II hydroxides are strong bases.
(1) - This is the strongest acid, as HCl is on the list of the strong acids.
(2) - This is the second strongest acid. Ammonium chloride is a relatively weak base.
(3) - This is the second to last weakest acid. Sodium ethanoate is a stronger base than ammonium chloride, but still weaker than NaOH.
