Babu took some quantity of dilute nitric acid in a test tube and heated the test tube at 70°C for about 10minutes. What was its effect on the pH of nitric acid?

Correct option is D

The Correct  Ans is Option D) It is decreased

• Heating dilute nitric acid (HNO₃) at 70°C would likely lead to an increase in the dissociation of the acid, resulting in a slight increase in the concentration of hydrogen ions (H⁺) in the solution. However, nitric acid is a strong acid and dissociates almost completely in aqueous solutions at room temperature.
• Therefore, even at a higher temperature like 70°C, the dissociation remains nearly complete, and the pH will still be low.

In practice, the effect of heating on the pH of dilute nitric acid is minimal because:

1. Nitric acid is a strong acid and already dissociates completely in water.
2. The temperature increase may cause a slight increase in ionization, but not enough to drastically change the pH, as the acid is already fully dissociated.

Thus, the pH of the dilute nitric acid will likely stay quite low, around 1 to 2, and will not change significantly by heating it to 70°C for 10 minutes.