Vapour pressure and Raoult's law
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See all →- 5 moles of liquid X and 10 moles of liquid Y make a solution having a vapour pressure of 70 torr. The vapour pressures of pure X and Y are 63 torr and 78 torr respectively. Which of the following is true regarding the described solution? Answer: 2. The solution shows negative deviation. Key idea: compare the observed vapour pressure with the Raoult's law value. x_X=5/15=1/3 ,... 1
- The correct option for the value of vapour pressure of a solution at 45^° C with benzene to octane in molar ratio 3 : 2 is :[At 45^° C vapour pressure of benzene is 280 mm Hg and that of octane is 420 mm Hg. Assume Ideal gas] Answer: 3. 336 mm of Hg Key idea: Raoult's law for an ideal solution: P=x₁P₁^°+x₂P₂^° . x_benzene=3/5=0.6 , x_octane=2/5=0.4 . P=0.6(280)+0.... 1
- Which of the following statements about the composition of the vapour over an ideal 1 : 1 molar mixture of benzene and toluene is correct ? Assume that the temperature is constant at 25°C. (Given, Vapour Pressure Data at 25°C, benzene = 12.8 kPa, tol… Answer: 1. The vapour will contain a higher percentage of benzene. Key idea: the component with the higher vapour pressure is more volatile... 1