Rank these from lowest to highest pH without using a data table:
NaF NaCl AlCl3
You need to know how the salts hydrolyze.
NaF is the salt of a strong base (NaOH) and weak acid (HF); therefore, it is basic.
F^- + HOH ==> HF + OH^-
NaCl is the salt of a strong base (NaOH) and a strong acid (HCl); therefore, it is neutral.
Na^+ nor Cl^- hydrolyze.
AlCl3 is the salt of a weak base [Al(OH)3] and a strong acid (HCl); therefore, it is acidic.
Al^+3 + HOH ==> Al(OH^-)^+2 + H^+
[This isn't the real equation for what goes on but it's close.]