NEET levelSingle correct optionDifficulty 1 of 3rg122
The van der Waals equation for n moles of a gas is
A(P+V2a)(V−b)=nRT
B(P+V2an2)(V−nb)=nRT
C(P−V2an2)(V+nb)=nRT
D(P+Van)(V−b)=nRT
Answer: B
The pressure correction scales with the square of the number density, giving an2/V2, and the excluded volume scales with n, giving nb. Both corrections are added or subtracted so as to recover the ideal pressure and free volume.