What is the chemically correct mixture ratio for fuel to air?

The correct ratio for a chemically balanced mixture of fuel to air in a combustion process is primarily expressed in terms of fuel to air. For combustion engines, the ideal air-fuel ratio for complete combustion of gasoline is approximately 14.7 parts of air to 1 part of fuel, which is often rounded to a 15:1 ratio when considering stoichiometric mixtures.

In this context, when expressing the mixture ratio as “air to fuel,” a 15:1 ratio translates to 1 part of fuel for every 15 parts of air, making it equivalent to the ideal stoichiometric ratio necessary for maximizing combustion efficiency and minimizing emissions. Thus, when evaluating mixtures, recognizing that a ratio of 15:1 (air to fuel) means there is an excess of air available to fully combust the given amount of fuel aligns with standard combustion principles, hence making option B the most accurate choice.