Which from following gases is least soluble in water at same temperature and pressure ?

Which of the following ethers is gaseous at room temperature ?

A container contains mixture of He and Ne gases at certain temperature. He is 20 % by mass of mixture. What is the ratio of partial pressure of Helium to Neon ?

1 mole of an ideal gas is compressed isothermally and reversibly from initial pressure $x$ kPa to final pressure $2x$ kPa at 300 K. Find the work done $(R = 8.314\ \text{J K}^{-1}\text{mol}^{-1})$