Which of the following formulas is correctly represented according to Stock notation?

In which of the following reactions is no gas evolved on the product side? (Temperature is maintained below the boiling point of liquids formed)

Which of the following has the maximum mass?

Mole fraction of $O_2$ in $O_2$ and $O_3$ mixture is $0.25$. Hence percentage concentration $\left( \frac{w}{W} \% \right)$ of $O_2$ in the mixture is:

When $800 \ mL$ of $0.5 \ M$ nitric acid is heated in a beaker,its volume is reduced to half and $11.5 \ g$ of nitric acid is evaporated. The molarity of the remaining nitric acid solution is $x \times 10^{-2} \ M$. (Nearest Integer) (Molar mass of nitric acid is $63 \ g \ mol^{-1}$)

The correct order of the total number of atoms present in
$(A)$ $2$ moles of cyclohexane
$(B)$ $684 \text{ g}$ of sucrose
$(C)$ $90.8 \text{ L}$ of dihydrogen at $STP$
is: