D$5.$ Ethane is burned to give flue gas of the following composition $(\frac{v}{v}\%)$ on a dry

basis:$-$

How much excess air was added $($based upon complete combustion$),$ and

what percentage of the carbon was completely oxidised?

$($Ans: $($a$)7\mathrm{.}17\%,($b$)95\mathrm{.}0\%)$