Vapour pressure of pure 'A' is 70 mm of Hg at $$25^0C$$ it forms an ideal solution is with 'B' in which mole fraction of A is 0.8. If the vapour pressure of the solution is 84 mm is Hg at $$25^0C$$, the vapour pressure of pure 'B' at $$25^0C$$ is :

A solution is prepared by mixing $${\text{8}}{\text{.5}}\,{\text{g}}$$ of $${\text{C}}{{\text{H}}_{\text{2}}}{\text{C}}{{\text{l}}_2}$$ and $$11.95\,{\text{g}}$$ of $${\text{CHC}}{{\text{l}}_{\text{3}}}$$. If vapour pressure of $${\text{C}}{{\text{H}}_{\text{2}}}{\text{C}}{{\text{l}}_{\text{2}}}$$ and $${\text{CHC}}{{\text{l}}_3}$$ at $${\text{298}}\,{\text{K}}$$ are $$415$$ and $$200\,{\text{mm}}$$ Hg respecetively, then mole fraction of $${\text{CHC}}{{\text{l}}_{\text{3}}}$$ in vapour form is:

The kinetic energy of $$1\ mole$$ of gas is equal to-

Pressure exerted by 2 grams of helium present in a vessel is 1.5 atm. If 4 grams of gas 'X' is introduced into the same vessel keeping the condition constant, the pressure is 2.25 atm. Gas 'x' is  

The figure shows the graphs of pressure versus density for an ideal gas at two temperatures, $$T_1$$ and $$T_2$$, according to this which is correct?

The value of gas constant per mole is approximately-

Two gases X and Y have densities, $${d_{(x)}} = 3{d_{(y)}}$$ and molecular masses, $${M_{(x)}} = 0.5{M_{(y)}}$$. Then, the ratio of their pressures, i.e, $${P_x}:{P_y}$$ would be 

The vapour pressure of water at T(K) is 20 mm Hg. The following solutions are prepared at T(K) :

Two flasks of equal volume, connected by a narrow tube of negligible volume, contain $$2$$ moles of $$H_2$$ gas at $$1$$ atm pressure and $$300$$ K. Now, one of the flasks are heated to $$400$$ K and the other is maintained at $$300 K$$, then find final pressure: