Fractional Distillation of Nitric Acid-Water System

What happens to the nitric acid-water system if approximately 10% of nitric acid by mass is fractionally distilled?

A. Nitric acid content in the distillate increases

B. Nitric acid content in the distillate decreases

C. Nitric acid content in the residue increases

D. Nitric acid content in the residue decreases

Answer:

The correct answer is option C: Nitric acid content in the residue increases.

When approximately 10% of nitric acid by mass is fractionally distilled from a nitric acid-water system, the more volatile component tends to vaporize and subsequently condense as the distillate. Since water is more volatile than nitric acid, the fractionally distilled component will primarily be water. Thus, the nitric acid content in the distillate decreases (Option B), leaving behind a residue that is now richer in nitric acid - meaning the nitric acid content in the residue increases.

In the nitric acid-water system, when approximately 10% of nitric acid by mass is fractionally distilled, the distillate will have an increased nitric acid content, while the residue will have a decreased nitric acid content. This is because distillation is a process that separates components with different vapor pressures. Nitric acid, being more volatile than water, will vaporize and condense in the distillation process, leading to a higher concentration of nitric acid in the distillate. On the other hand, the residue will contain less nitric acid since most of it has been separated in the distillate.