BITSAT2021ChemistrySolutionsActual
Liquids A and B form an ideal solution in the entire composition range. At 350 ~K , the vapor pressures of pure A and pure B are 7 10³ ~Pa and 12 10³ ~Pa , respectively. The composition of the vapour is in equilibrium with a solution containing 40 mole percent of A at this temperature is:
Options
- Ax_ A =0.37 ; x_ B =0.63
- Bx_ A =0.28 ; x_ B =0.72
- Cx_ A =0.4 ; x_ B =0.6
- Dx_ A =0.76 ; x_ B =0.24
Correct answer
B. x_ A =0.28 ; x_ B =0.72
Step-by-step solution
P _ A ^ =7 10³ P _ B ^ =12 10³x_ A ^ =0.4 ; x_ B ^ =1-0.4x_ B ^ =0.6 P _ total = P _ A ^ ^ x_ A ^ + P _ B ^ x_ B ^ =7 10³ 0.4+12 10³ 0.6=(7 0.4+12 0.6) 10³=10⁴x_ A = P _ A ^ ^ x^ A P _ total = 7 10³ 0.4 10⁴ x_ A =0.28, x_ B =1-0.28=0.72