Question

Heptane and octane form an ideal solution. At 373K , the vapour pressure of the two liquids are 105.0 kPa and 46.0 kPa, respectively. What will be the vapour pressure, of the mixture of 25g of heptane and 35g of octane ? Select the correct answer from above options

Answer 1

Correct Answer - 73.43kPa p ∘ heptene =105.2kPa,p ∘ octane =46.28kPa Mw of heptane (C7H16)=100 Mw of octane (C8H18)=114 Moles of heptane = 26 100 =0.26 Moles of octane = 35 114 =0.31 CHMiheptane= 0.26 0.26+0.1 =0.456 CHMioctane=1-0.456=0.544 pheptane=p ∘ heptane ×CHMiheptane =105.2×0.456=47.97kPa poctane=p ∘ ocatne ×CHMioctane =46.8kPa×0.544=25.46kPa ptotal=47.97+25.46=73.43kPa