Formic acid is the simplest carboxylic acid, HCOOH. It is the cause of pain in b
ID: 994394 • Letter: F
Question
Formic acid is the simplest carboxylic acid, HCOOH. It is the cause of pain in bee and ant stings and nearly a million tonnes are made each year because it is a good preservative. In water, formic acid behaves as a weak acid:
HCOOH(aq) + H2O(l) ? HCOO(aq) + H3O+(aq)
The concentration of formate ions (HCOO-) is increased by adding sodium formate (HCOONa). Which of the statements below is the best explanation of the process of returning to equilibrium after the sodium formate has been added?
a. The H3O+ concentration will decrease, because some will react with HCOO- to return to the equilibrium product/reactant ratio.
b. The H3O+ concentration will increase, because the ratio of H3O+ to HCOO- remains constant at equilibrium.
c. The HCOOH concentration will decrease, because it reacts with the added HCOONa.
d. The HCOO- concentration will increase and concentration of the other species will decrease to balance the reaction.
Explanation / Answer
a