Question

Absolute alcohol can be obtained from rectified spirit

• A. By removing the water in it using concentrated sulphuric acid
• B. By removing the water using phosphorus pentoxide
• C. By distilling with the appropriate amount of benzene
• D. By distilling over plenty of quick lime

Answer 1

Answer: (C)

Absolute alcohol is $99\%$ pure alcohol. Rectified spirit contains $95.8796$ ethanol and $4.13^{\circ }$ water. Absolute alcohol can be prepared from rectified spirit by azeotropic distillation. Azeotropic distillation is the use of a third component to separate two close-boiling components, usually refers to the specific technique of adding another component to generate a new, lower-boiling azeotrope. For example-with the addition of benzene to water and ethanol.