As observed from Andrew's isotherms of ${\mathrm{CO}}_2,$ the critical temperature of ${\mathrm{CO}}_2$ is ________$º\mathrm{C}.$

The escape velocity is given by:

$\mathrm{v}=\sqrt{2\mathrm{gr}}$

where, $\mathrm{r}=6.37\times {10}^6 \mathrm{m}$ for the earth. At what temperature will the $\mathrm{RMS}$ velocity of an ${\mathrm{H}}_2$ molecule attain the escape velocity? The temperature is $\mathrm{a}\times {10}^4 \mathrm{K}.$ Find the value of $\text{'}\mathrm{a}\text{'}$ correct up to two places of decimal.

$50$ drops each of water and ether, weigh $3.64 \mathrm{g}$ and $0.852 \mathrm{g}$, respectively. Determine the surface tension of ether, if the surface tension of water is $72.75 \mathrm{dyne} {\mathrm{cm}}^{-1}$.

Give an answer to the nearest integer value.

The minimum pressure (in $\mathrm{bar}$) required to compress $500 {\mathrm{dm}}^3$ of air at $1 \mathrm{bar}$ to $200 {\mathrm{dm}}^3$ at $30°\mathrm{C}$ is $\frac{\mathrm{P}}{2}$ bar. The value of $\mathrm{P} \mathrm{is}$