$A$ gas has a density of $2.68 \ g/L$ at $STP$. Identify the gas.

The normality of $H_{2}SO_{4}$ in the solution obtained on mixing $100 \ mL$ of $0.1 \ M \ H_{2}SO_{4}$ with $50 \ mL$ of $0.1 \ M \ NaOH$ is $\times 10^{-1} \ N$. (Nearest Integer)

Which of the following compounds does not have similarity in their structural aspect?

$A$ person coming out of a swimming pool has $30 \ g$ of water on their body. How much heat in $kJ$ is required to evaporate this water? (The latent heat of vaporization of water is $40.79 \ kJ \ mol^{-1}$)

How many moles of aluminum oxide $(Al_2O_3)$ are produced when $1 \text{ mole}$ of potassium chlorate $(KClO_3)$ undergoes thermal decomposition,and the resulting gaseous product is reacted with excess aluminum?

Rearrange the following ($I$ to $IV$) in the order of increasing masses and choose the correct answer (Atomic mass: $N=14, O=16, Cu=63$).
$I.$ $1$ molecule of oxygen
$II.$ $1$ atom of nitrogen
$III.$ $1 \times 10^{-10} \ g$ molecular weight of oxygen
$IV.$ $1 \times 10^{-10} \ g$ atomic weight of copper