Question

For each solution whose pH value deviated from 7.0 by at least 1.0 pH unit, give an equation accompanied by a statement which gives the reasons and/or explanation for the deviation.

pH values:
NaCl 6.89
NaC2H3O2 7.75
Na2CO3 11.20
Cu(NO3)3 4.73
NH4Cl 5.91
Zn(NO3)2 5.20
KAl(SO4)2 3.70
NaHCO3 8.82

Answer 1

NaCl doesn't deviate more than 1 pH unit from 7.0.
Same for NaC2H3O2.
Hydrolysis of Co3^2- accounts for the higher pH.
CO3^2- + HOH ==> HCO3^- + OH^-

Hydrolysis of NH4Cl accounts for the lower pH.
NH4^+ + H2O ==> NH3 + H3O^+
etc.