Air contains $23\% \, O_2$ and $77\% \, N_2$ by weight. What is the percentage of $O_2$ by volume?

The ratio of $C_p$ and $C_v$ of a gas '$X$' is $1.4$. The number of atoms of the gas '$X$' present in $11.2 \ L$ of it at $N.T.P.$ is

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)

What is $Rasavidya$?

Match the following columns:

Column - $A$	Column - $B$
$(A)$ $88 \ g$ of $CO_2$	$(1)$ $0.2 \ mol$
$(B)$ $6.022 \times 10^{23}$ molecules of water	$(2)$ $2 \ mol$
$(C)$ $5.6 \ L$ of $O_2$ at $STP$	$(3)$ $1 \ mol$
$(D)$ $96 \ g$ of $O_2$	$(4)$ $6.022 \times 10^{23}$ molecules
$(E)$ One mole of any gas at $STP$	$(5)$ $3 \ mol$

An athlete is given $100 \ g$ of glucose $(C_6H_{12}O_6)$ for energy. This is equivalent to $1800 \ kJ$ of energy. The $50 \ \%$ of this energy gained is utilized by the athlete for sports activities at the event. In order to avoid storage of energy,the weight of extra water he would need to perspire is $......... \ g$ (Nearest integer).
Assume that there is no other way of consuming stored energy. Given: The enthalpy of evaporation of water is $45 \ kJ \ mol^{-1}$.
Molar mass of $C, H$ and $O$ are $12, 1$ and $16 \ g \ mol^{-1}$.