Salts - Acidic, Basic, or Neutral?
LiClO4
Neutral Li+, first column in periodic table, therefore neutral ClO4-, conjugate acid is the strong acid HClO4
NaNO₃
Neutral Na+, first column in periodic table, therefore neutral NO3-, conjugate acid is a strong acid, therefore it is neutral
C6H5NH3NO2 C6H5NH3+ Ka = 2.50 x 10-5 NO2- Kb = 2.50 x 10-11
Acidic C6H5NH3+, conjugate base is a weak base, therefore it is potentially acidic NO2-, conjugate acid is a weak acid, therefore the salt is also potentially basic However, since the Ka > Kb, the solution must be acidic
NH4Br
Acidic NH4+, conjugate base is a weak base, therefore it is acidic Br-, conjugate acid is a strong acid, therefore it is neutral
K2CO3
Basic K+ comes from the first column in the periodic table, so it is neutral. CO3^2- has the conjugate acid HCO3^-, which is a weak acid, therefore it is a weak base.
KCN
Basic K+, first column in periodic table, therefore neutral CN-, conjugate acid is the weak acid HCN, therefore it is basic
RbF
Basic Rb+, first column in periodic table, therefore neutral F-, conjugate acid is the weak acid HF, therefore it is basic