The moles of methane required to produce 81 g of water after complete combustion is ______ x 10^-2 mol. (nearest integer)

${\mathrm{CH}}_4 + 2{\mathrm{O}}_2 \to {\mathrm{CO}}_2 + 2{\mathrm{H}}_2\mathrm{O}$

POAC on H atom

${\mathrm{n}}_{{\mathrm{CH}}_4} \mathrm{x} 4 = {\mathrm{n}}_{{\mathrm{H}}_2\mathrm{O}} \mathrm{x} 2$

${\mathrm{n}}_{{\mathrm{CH}}_4} = \frac{81}{18} \mathrm{x} 2 \mathrm{x} \frac{1 }{4} = \frac{81}{36}$

${\mathrm{n}}_{{\mathrm{CH}}_4} = 2.25$

$= 225 \mathrm{x} {10}^{-2}$

Nearest Integers = 225