Ncert Solutions Chemistry Class 11th

Number of mole of $\mathrm{X}=\frac{6.022\times {10}^{22}}{6.022\times {10}^{23}}=\frac{10}{\text{Molar mass of}\mathrm{X}}$

So molar mass of $X=100\mathrm{g}$

Molarity $=\frac{5}{100\times 2}=0.025\mathrm{M}$

Ans. $=0.025\mathrm{M}$

$\mathrm{M}=25\times {10}^{-3}$

So $P=25$

Kindly consider the following Image 

At room temperature water is liquid and has boiling point 373K due to hydrogen bonding. Where as H? S is gas and it has no hydrogen bonding. Hence boiling point of H? S is less than 300K [Boiling point of H? S is -60 °C ].

Burning of fossil fuels (which contain sulphur and nitrogenous matter) such as coal and oil in power stations and furnaces produce sulphur dioxide and nitrogen oxides which causes acid rain.