Final answer:
The mole ratio of ethane to water in the combustion reaction is 1:3, which is also equivalent to 2:6.
Step-by-step explanation:
The mole ratio of ethane to water in the given reaction, 2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O, can be determined by comparing the coefficients in front of each substance in the balanced equation. The coefficient in front of ethane (C₂H₆) is 2, and the coefficient in front of water (H₂O) is 6. Therefore, for every 2 moles of ethane that react, 6 moles of water are produced, giving us a mole ratio of ethane to water of 1:3 or, equivalently, 2:6.