Eight liters of liquid iso$-$octane and $4$ liters of liquid n$-$heptane are mixed and burned

with $10\%$ excess air. Because of faulty combustion, fractional conversion of $90\%$

octane and $95\%$ heptane are achieved. Of the fuel burned, $95\%$ forms CO$2,$ the rest to CO$.$ Determine $($a$)$ moles of air required in kmol $($b$)$ complete analysis of the stack

gas $($c$)$ concentration of CO $($in ppm$)$ in the stack gas.