Solution:
Concept- A basic solution as a result of the reaction between a strong base and a weak acid.Now, ammonium acetate is a solution mixture of a weak base ammonium hydroxide and a weak acid acetic acid. Thus, it can’t be basic in nature .
Calcium carbonate is salt of strong base calcium hydroxide and weak acid but still it is not basic in solution as it is insoluble in water.
Ammonium sulphate is a salt of weak base ammonium hydroxide and strong acid sulphuric acid, thus it is not basic in nature.
Now, sodium acetate is a mixture of a strong base sodium hydroxide and a weak acid acetic acid, thus, its 1 M solution is basic.
Hence, the correct option is (4).
