Question

95% ethyl alcohol can be converted to 100% ethyl alcohol by:

• A. magnesium chloride
• B. calcium oxide
• C. magnesium phosphate
• D. magnesium sulphate

Answer 1

Answer: (B)

calcium oxide

Absolute alcohol is named to 100% concentrated ethanol. A rectified spirit is a mixture with a composition of ethanol 95% and water with 5%. However, to attain a pure form of ethanol, one more separation step is required, so that the water content in rectified spirit is removed completely. Based on the chemical nature of ethanol and water, their concentration in the liquid mixture does not alter when heated to its boiling point.One method was using quicklime (CaO) to absorb water content and finally contacting the solution with anhydrous copper sulphate removes the leftover traces of water.