Will 010 M aqueous solutions of the following salts be acidi

Will 0.10 M aqueous solutions of the following salts be acidic , basic or neutral?
(neutral if its pH is 7.00±0.05).

a) sodium chloride (NaCl)
b) ammonium hydrogen sulfite (NH₄HSO₃)
c) sodium sulfate (Na₂SO₄)
d) ammonium sulfide ((NH₄)₂S)
e) ammonium formate (NH₄CHO₂)

Solution

Remember these rules:
strong acid + strong base --> neutral solution
weak acid + strong base --> weak base
weak base + strong acid --> weak acid
weak acid + weak base --> neutral solution

A) NaCl

NaCl is neutral becuase it is made up of Na+(aq) the conjugate acid of a strong base (NaOH) and Cl-(aq) the conjugate base of a strong acid (HCl).

b)For NH4HSO3: NH4+(aq) and HSO3-(aq) are both acids because both can donate hydrogen ions. You already know NH4+ is an acid but HSO3- can also donate one of its hydrogen ions. A weak acid plus a weak acid makes a weak acid, so NH4HSO3 is acidic.

c)sodium sulfate - NEUTRAL
strong base (NaOH) + strong acid (H2SO4) = neutral

d) The first one has ions of NH4+ and
S2-(aq). NH4+(aq) is a acid, it can donates one of its hydrogens. S2-(aq) is a base, it can accept hydrogen ions. NH4+(aq) is a weak acid because its Ka is on the low side and S2- is a strong base because its Kb is on the high side. A weak acid plus a strong base makes a weak base. The reaction proceeds:
NH4+(aq) + S2-(aq) --> HS-(aq) + NH3(aq)
Both HS-(aq) and NH3(aq) are weak bases, so (NH4)2S is basic.

e) ammonium formate (NH4CHO2) is acidic

NH4CHO2 comes from NH3 and HCHO2.

Kb NH3 = 1.8 x 10^-5
Ka HCHO2 = 1.8 x 10^-4

Since Ka>Kb, the salt solution is acidic.