Saved Bookmarks
| 1. |
Gas 'A' (Molar Mass of A =128 g "mol"^(-1)) is taken in a closed container at the initial total pressure of 1000 mm of Hg.Pressure of the gas decreases to 900 mm in 5 seconds due to the diffussion through square cross section.Another similar size container is taken in which gaseous mixture of A and B are taken.(Molar mass of the mixture 472/5) at the total pressure of 5000 mm (molar mass of B =72 g "mol"^(-1)).A reactangular cross-section is made in this container and gases are allowed to diffuse.Width of this rectangular cross-section is same as the side of the square cross section and length of the rectangular cross-section is 50% more than the width.Assume that the gases A and B are non reacting and rate of diffusion of the gases are only dependent upon the initial total pressure and it is independent of the change in the pressure due to diffusion.Assume all other conditions to be identical. Ratio of the number of moles of A and B left in the container after 10 seconds from the diffusion starts is : |
|
Answer» `7/9` In the mixture `M_(mix)=X_AM_A+(1+X_A)M_Bimplies 472/5=X_Axx128+(1-X_A)72` `472/5=56X_A+72 IMPLIES 472=280X_A+360` `X_A=112/280=5/2,X_B=3/5` The mixture `r_A/r'_A=(P_A'.A'_1)/(P_A A_2)implies r_A/r'_A=1/2xx X^2/(x x(3x)/2)=1/3` `r'_A=3r_A=3xx20=60 "torr"//s " " implies r'_A^@/r'_B^@=P'_A/P'_Bsqrt(M_B/M_A)=2/3xxsqrt(72/128)=1/2` `r'_B=120` torr/s After 10 sec `P''_A=2000-60xx10=1400` torr `P''_B=3000-120xx10=1800` torr `n''_A/n''_B=7/9` |
|