Consider the following reaction occurring in the blast furnace:

$$\mathrm{Fe}_3 \mathrm{O}_{4(\mathrm{~s})}+4 \mathrm{CO}_{(\mathrm{g})} \rightarrow 3 \mathrm{Fe}_{(\mathrm{l})}+4 \mathrm{CO}_{2(\mathrm{~g})}$$

' $x$ ' kg of iron is produced when $2.32 \times 10^3 \mathrm{~kg} \mathrm{Fe}_3 \mathrm{O}_4$ and $2.8 \times 10^2 \mathrm{~kg} \mathrm{CO}$ are brought together in the furnace. The value of ' $x$ ' is _________ . (nearest integer)

{Given: molar mass of $\mathrm{Fe}_3 \mathrm{O}_4=232 \mathrm{~g} \mathrm{~mol}^{-1}$

molar mass of $\mathrm{CO}=28 \mathrm{~g} \mathrm{~mol}^{-1}$

molar mass of $\mathrm{Fe}=56 \mathrm{~g} \mathrm{~mol}^{-1}$}

Xg of benzoic acid on reaction with aq $\mathrm{NaHCO}_3$ released $\mathrm{CO}_2$ that occupied 11.2 L volume at STP.

X is _________ g.

Standard entropies of $\mathrm{X}_2, \mathrm{Y}_2$ and $\mathrm{XY}_5$ are 70, 50 and $110 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}$ respectively. The temperature in Kelvin at which the reaction

$$\frac{1}{2} \mathrm{X}_2+\frac{5}{2} \mathrm{Y}_2 \rightleftharpoons \mathrm{XY}_5 \Delta \mathrm{H}^{\ominus}=-35 \mathrm{~kJ} \mathrm{~mol}^{-1}$$

will be at equilibrium is __________ (Nearest integer)

$\lim _\limits{x \rightarrow 0} \operatorname{cosec} x\left(\sqrt{2 \cos ^2 x+3 \cos x}-\sqrt{\cos ^2 x+\sin x+4}\right)$ is: