The correct balanced chemical equation for the combustion of ethane (C2H6) in oxygen gas (O2) to form water (H2O) and carbon dioxide (CO2) is:

2C2H6 + 7O2 → 4CO2 + 6H2O

In this equation:

- Two molecules of ethane (2C2H6) react with seven molecules of oxygen gas (7O2).

- Four molecules of carbon dioxide (4CO2) are produced.

- Six molecules of water (6H2O) are produced.

This equation is balanced because the number of atoms of each element is the same on both sides of the equation.