Question

What is the nitric acid – water composition by mass, respectively, for the components to form an azeotrope?

(a) 70% – 30%

(b) 68% – 32%

(c) 30% – 70%

(d) 32% – 68%

I have been asked this question during an interview for a job.

The above asked question is from P-Block Elements in section P-Block Elements of Chemistry – Class 12

Answer 1

The correct answer is (b) 68% – 32%

Best explanation: Experimentally, it is determined that nitric acid and water form a constant boiling azeotrope at 68% – 32% by mass composition, respectively. Here, it becomes impossible to separate water and nitric acid by distillation methods. Thus, concentrated sulfuric acid is used for dehydration and removal of water.