We’re being asked to determine principal acid-base equilibrium when KNO2 is dissolved in water.
Ionic salts are made up of positively charged ion (cation) and a negatively charged ion (anion). To determine if the ionic salt would be acidic, basic, or neutral, we need to identify the acidity or basicity of the cation and anion.
• transition metal
▪ charge of +2 or higher → acidic
▪ less than +2 → neutral solution
• main group metal
When KNO2 is dissolved in water, which of the following is the principal acid-base equilibrium?
A) NO2- (aq) + H2O(l) ⇌ HNO2(aq) + OH-(aq)
B) HNO2(aq) ⇌ H+ (aq) + NO2-(aq)
C) K(H2O)6+(aq) ⇌ K(H2O)5OH(aq) + H+ (aq)
D) NO2- (aq) + H2O (l) ⇌ HNO3(aq) + H+ (aq)