Equal weights of $X$ (atomic weight $= 36$) and $Y$ (atomic weight $= 24$) are reacted to form the compound $X_2Y_3$. Which of the following is correct?

$A$ mixture of $100 \ mmol$ of $Ca(OH)_2$ and $2 \ g$ of $Na_2SO_4$ was dissolved in water and the volume was made up to $100 \ mL$. The mass of $CaSO_4$ formed and the concentration of $OH^{-}$ in the resulting solution,respectively,are:
(Molar mass of $Ca(OH)_2$,$Na_2SO_4$ and $CaSO_4$ are $74$,$142$ and $136 \ g \ mol^{-1}$ respectively; $K_{sp}$ of $Ca(OH)_2$ is $5.5 \times 10^{-6}$)

When $400 \ mL$ of $0.2 \ M \ H_2SO_4$ solution is mixed with $600 \ mL$ of $0.1 \ M \ NaOH$ solution,the increase in temperature of the final solution is $...... \times 10^{-2} \ K$. (Round off to the Nearest Integer).
$\left[ \text{Use } : H^{+}_{(aq)} + OH^{-}_{(aq)} \rightarrow H_2O : \Delta_{r}H = -57.1 \ kJ \ mol^{-1} \right]$
Specific heat of $H_2O = 4.18 \ J \ K^{-1} \ g^{-1}$
Density of $H_2O = 1.0 \ g \ cm^{-3}$
Assume no change in volume of solution on mixing.

Identify the values of $A$,$B$,$C$,$D$ and $E$ for the following unbalanced reaction: $aKNO_3 + 5C_{12}H_{22}O_{11} \rightarrow bN_2 + cCO_2 + dH_2O + eK_2CO_3$

In Ostwald's process for the manufacture of nitric acid,the first step involves the oxidation of ammonia gas by oxygen gas to give nitric oxide gas and steam. What is the maximum weight of nitric oxide that can be obtained starting only with $10.00 \ g$ of ammonia and $20.00 \ g$ of oxygen?

$A$ mixture containing $64.0 \ g$ of $H_2$ and $64.0 \ g$ of $O_2$ is reacted so that water is formed as follows:
$2H_2 + O_2 \rightarrow 2H_2O$
Which of the following statements is/are correct?