Strong acid + strong base = neutral salt;
strong acid + weak base = acidic salt;
weak acid + strong base = basic salt;
weak acid + weak base = it depends on the relative strength of the acid and base.
1. NaOH is a strong base; CH3COOH is a weak acid. The resulting salt, CH3COONa, will be basic (b).
2. HBr is a strong acid; NH3 is a weak base. The resulting salt, NH4Br, will be acidic (c).
3. H2SO4 is a strong acid; Ca(OH)2 is a strong base. The resulting salt, CaSO4, will be neutral (a).