Question

Determine the Bancroft temperature (if it exists) for:

i) Benzene and 2-propanol

ii) Acetone and Water

iii) Iso-octane and Water

Answer 1

Answer:

Bancroft temperature or Azeotrope:

1) It is the mixture of two or more liquids with constant boiling point. Hence it is called constant boiling point mixture.

2) This mixture at the boiling point it shows the equal proportion of vapour pressure of individual liquids.

i) Benzene and 2-propanol:

Isopropanol BP = 82.5⁰C

Benzene BP = 80.2⁰C

Boiling point of mixture (Bancroft temperature) = 71.9⁰C

ii) Acetone and Water:

Acetone BP = 56.5⁰C

water BP = 100⁰C

Boiling point temperature difference is more. Hence can not form the Azeotrope mixture (Bancroft temperature).

iii) Iso-octane and Water:

Iso octane BP = 99⁰C

water BP = 100⁰C