Which one of the following equations represents the variation of viscosity coefficient $(\eta)$ with temperature $(T)$?

Densities of two gases are in the ratio $1:2$ and their temperatures are in the ratio $2:1$,then the ratio of their respective pressures is

$1 \text{ mole}$ of gas $A$ and $1 \text{ mole}$ of gas $B$ at $27^{\circ} C$ were pumped into a $24.6 \ L$ volume pre-evacuated isolated flask. The catalyst coated inside the flask catalyses the following reaction $A_{(g)} + B_{(g)} \longrightarrow 2 D_{(g)}$. The kinetic energy of $D$ is $98.03 \ L \ atm$. Calculate the pressure realized at the end of the reaction. (in $atm$)

The correct value of the universal gas constant $R$ is:

The density of a mixture of $He$ and $O_2$ gases at $27\,^{\circ}C$ and $760\, torr$ pressure is $0.543\, g\, dm^{-3}$. Calculate the percentage by mass of $He$ in the mixture.

At $STP$,$0.50 \ mol$ $H_2$ gas and $1.0 \ mol$ $He$ gas: