How is concentrated $H_2SO_4$ diluted?

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

Select the correct option based on the given figure. Symbol $T$ indicates a true statement and $F$ indicates a false statement.
Solution $P = 8 \, N$ $H_2SO_{4(aq)}$ and Solution $Q = 8 \, N$ $HNO_{3(aq)}$.
$(1)$ The number of moles of solute in solution $P$ and solution $Q$ are equal.
$(2)$ The number of gram-equivalents of solute in solution $P$ and solution $Q$ are equal.
$(3)$ The mole fraction of solvent in solution $P$ and solution $Q$ are equal.
$(4)$ The concentration of $H^+_{(aq)}$ in solution $P$ and solution $Q$ are equal.

Which of the following substances represents calcium chlorite?

$200 \ mL$ of a mixture of $50\% \ H_2$,$40\% \ CH_4$ and $10\% \ CO_2$ is exploded with excess of oxygen in an eudiometry tube. The resultant mixture is cooled to room temperature and is passed through $aq. KOH$. Find volume contraction after passing through $KOH$ ................. $mL$

Iron sulphide is heated in air to form $A$,an oxide of sulphur. $A$ is dissolved in water to give an acid. The basicity of this acid is: