Given a 1.0 L solution containing 0.1 moles NaNO2 and 0.1 moles HNO2, what is the net ionic equation upon the addition of a small amount of KOH?

Question

	H+ + H2O → H3O+
	OH- + NO2- → HNO3
	OH- + HNO2 → H2O + NO2-
	H+ + NO2- → HNO2
	OH- + H2O → H3O2-

Answer 1

A solution of HNO2 (a weak acid) and NaNO2 (the salt of the weak acid) makes a buffer solution.

HNO₂ + OH^- ==> H₂O + NO₂^- (the third option is correct)