From Avogadro's law, we know that

Volume of 1 mole of the gas = graw molecular mass $=22.4 \mathrm{~L}$ at STP

Volume occupied by $28 \mathrm{~g} \mathrm{CO}(1 \mathrm{~mol} \mathrm{CO})=22.4 \mathrm{~L}$ at STP

$\left(\because\right.$ Molar mass of $\left.\mathrm{CO}=12+16=28 \mathrm{~g} \mathrm{~mol}^{-1}\right)$

$\therefore \quad$ Volume occupied by $1 \mathrm{~g} \mathrm{~CO}=\frac{22.4}{28} \mathrm{~L}$ at STP

Similarly, volume occupied by $1 \mathrm{~g} \mathrm{~H}_2 \mathrm{O}=\frac{22.4}{18} \mathrm{~L}$ at STP

$\left(\because\right.$ Molar mass of $\left.\mathrm{H}_2 \mathrm{O}=(2 \times 1)+16=18 \mathrm{~g} \mathrm{~mol}^{-1}\right)$

Volume occupied by $1 \mathrm{~g} \mathrm{CH}_4=\frac{22.4}{16} \mathrm{~L}$ at STP

$\left(\because\right.$ Molar mass of $\left.\mathrm{CH}_4=12+(4 \times 1)=16 \mathrm{~g} \mathrm{~mol}^{-1}\right)$

Volume occupied by $1 \mathrm{~g} \mathrm{NO}=\frac{22.4}{30} \mathrm{~L}$ at STP

$\left(\because\right.$ Molar mass of $\left.\mathrm{NO}=14+16=30 \mathrm{~g} \mathrm{~mol}^{-1}\right)$

Thus, $1 \mathrm{~g} \mathrm{CH}_4$ will occupy maximum volume while 1 g of NO will occupy minimum volume at STP.

Physical properties of ice, water and steam are very different because they found in different states. Ice found in solid, water found in liquid and steam found in vapour states. The chemical composition of water in all the three states (ice, water and steam) is same, i.e., $\mathrm{H}_2 \mathrm{O}$.