Which Substance is a Reactant in the Following Chemical Equation

Question

Which substance is a reactant in the following chemical equation? CO2+ H2O ↔ H2CO3
A) water
B) carbon
C) oxygen
D) hydrogen
E) carbonic acid

Accepted Answer

The Answer is A

Which substance is a reactant in the following chemical equation? CO2 + H2O ↔ H2CO3