How many moles of CO2 must dissolve in excess water to produce 12 moles of H2CO3?

12 moles of CO₂.

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

CO₂ + H₂O —> H₂CO₃

From the balanced equation above,

1 mole of CO₂ dissolves in water (H₂O) to produce 1 mole of H₂CO₃.

Finally, we shall determine the number of mole of CO₂ needed to produce 12 moles of H₂CO₃. This can be obtained as follow:

From the balanced equation above,

1 mole of CO₂ dissolves in water (H₂O) to produce 1 mole of H₂CO₃.

Therefore, 12 moles of CO₂ will also dissolves in water (H₂O) to produce 12 moles of H₂CO₃.