Question

If dissolving carbon dioxide in water to form carbonic acid is the forward reaction, what is the reverse reaction that balances this reaction in chemical equilibrium?

Answer 1

Answer:

$H_2CO_3\rightleftharpoons H_2O + CO_2$

Explanation:

When carbon dioxide dissolves and reacts with water, the water and the gaseous  $CO_2$   reacts to form a dilute mixture solution of $H_2CO_3$ (carbonic acid ).

The reaction is   $H_2O + CO_2\rightleftharpoons H_2CO_3$

This is a forward reaction.  And the symbol   $\rightleftharpoons$  shows that the reaction can be reversible. It means that the reaction can be carried in forward direction as well as in the backward direction.

The reaction attains chemical equilibrium until the reactants and the products no longer changes with time.  

The carbonic acid can also dissociates into carbon dioxide and water in the backward direction.

$H_2CO_3\rightleftharpoons H_2O + CO_2$