A perfectly$-$mixed gaseous blend of $30\%$ methane CH$4$ and $70\%$ hydrogen H$2$ by

mass, is used as fuel for a modern spark ignition internal combustion engine. Answer

the following questions:

a$.$ Write and balance the stoichiometric combustion reaction for the gaseous blend.

b$.$ Evaluate the stoichiometric Air$-$to$-$Fuel ratio for the gaseous blend.