In which of the following cases is the absolute number of molecules of water minimum?

Question

Professor PC Thomas Classes · Answer

(c) : The number of molecules is directly proportional to the number of moles. (a) Mass = $1.8 \mathrm{~g}$, Moles = $1.8/18 = 0.1 \mathrm{~mol}$. (b) Moles = $0.18/18 = 0.01 \mathrm{~mol}$. (c) Moles = $11.2 \mathrm{~mL} / 22400 \mathrm{~mL} = 0.0005 \mathrm{~mol}$. (d) Moles = $0.001 \mathrm{~mol}$. The minimum number of moles is $0.0005 \mathrm{~mol}$, corresponding to $11.2 \mathrm{~mL}$ of water vapour at STP.