Question

Which of the following is the correct equation?

(a) CO2 + H2O H2CO3

(b) CO2 + H2O HCO3

(c) CO2 + H2O H3CO3

(d) CO2 + H2O H2CO2

This question was posed to me in unit test.

This intriguing question originated from Water as a Reactant in division Water Basics of Biochemistry

Answer 1

Right choice is (a) CO2 + H2O H2CO3

To elaborate: The correct balanced equation is CO2  + H2O H2CO3. Carbondioxide reacts with water to give carbonic acid.