Chemistry Physical Chemistry questions from JEE Main 2007.
A mixture of ethyl alcohol and propyl alcohol has a vapour pressure of $290 \mathrm{~mm}$ at $300 \mathrm{~K}$. The vapour pressure of propyl alcohol is $200 \mathrm{~mm}$. If the mole fraction of ethyl alcohol is $0.6$, its vapour pressure (in $\mathrm{mm}$) at the same temperature will be
A radioactive element gets spilled over the floor of a room. Its half-life period is $30$ days. If the initial activity is ten times the permissible value, after how many days will it be safe to enter the room?
Assuming that water vapour is an ideal gas, the internal energy $(\Delta \mathrm{U})$ when $1\mathrm{~mol}$ of water is vapourised at $1 \mathrm{~bar}$ pressure and $100^{\circ} \mathrm{C}$, (Given: Molar enthalpy of vapourization of water at $1 \mathrm{~bar}$ and $373 \mathrm{~K}=41 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and $\mathrm{R}=8.3 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}$ ) will be