The moles of methane required to produce $81 \mathrm{g}$ of water after complete combustion is____$\times {10}^{-2} \mathrm{mol}$. [nearest integer]

$116 \mathrm{g}$ of a substance upon dissociation reaction, yields $7.5 \mathrm{g}$ of hydrogen, $60 \mathrm{g}$ of oxygen and $48.5 \mathrm{g}$ of carbon. Given that the atomic masses of $\mathrm{H},\mathrm{O}$ and $\mathrm{C}$ are $1,16$ and $12$, respectively. The data agrees with how many formulae of the following?

A. ${\mathrm{CH}}_3\mathrm{COOH}$

B. $\mathrm{HCHO}$

C. ${\mathrm{CH}}_3{\mathrm{OOCH}}_3$

D. ${\mathrm{CH}}_3\mathrm{CHO}$

Compound $\mathrm{A}$ contains $8.7\%$ Hydrogen, $74\%$ Carbon and $17.3\%$ Nitrogen. The molecular formula of the compound is, Given : Atomic masses of $\mathrm{C},\mathrm{H}$ and $\mathrm{N}$ are $12,1$ and $14$ amu respectively.

The molar mass of the compound $\mathrm{A}$ is $162 \mathrm{g}{ \mathrm{mol}}^{-1}$.

Production of iron in blast furnace follows the following equation

${\mathrm{Fe}}_3{\mathrm{O}}_4\left(\mathrm{s}\right)+4\mathrm{CO}\left(\mathrm{g}\right)\to 3\mathrm{Fe}\left(\mathrm{l}\right)+4{\mathrm{CO}}_2\left(\mathrm{g}\right)$

when $4.640\mathrm{kg}$ of ${\mathrm{Fe}}_3{\mathrm{O}}_4$ and $2.520\mathrm{kg}$ of $\mathrm{CO}$ are allowed to react then the amount of iron (in $\mathrm{g}$) produced is :

[Given: Molar Atomic mass $\left({\mathrm{gmol}}^{-1}\right):\mathrm{Fe}=56$

Molar Atomic mass $\left({\mathrm{gmol}}^{-1}\right):\mathrm{O}=16$

Molar Atomic mass $\left({\mathrm{gmol}}^{-1}\right):\mathrm{C}=12$]