$13\mathrm{.}17$ Methane $($CH$4)$ enters a furnace and burns completely with $150\%$ of theoretical air entering at $250$C$,0\mathrm{.}945$ bar, $75\%$ relative humidity. Determine a$.$ the balanced reaction equation. b$.$ the dew point temperature of the combustion products, in oc$,$ when cooled at $0\mathrm{.}945$ bar. $52\mathrm{.}9$