Question

The reaction of zinc with dilute and concentrated nitric acid, respectively, produces :

• A. $N_2O$ and $NO_2$
• B. $N_2O$ and NO
• C. NO and $N_2O$
• D. $NO_2$ and $N_2O$

Answer 1

The Correct Option is A

The reaction of zinc with nitric acid depends on the concentration of the acid. Let's explore the reactions with both dilute and concentrated nitric acid:

1. When zinc (Zn) reacts with dilute nitric acid (HNO_3), the acid is not strong enough to completely oxidize zinc to NO_2. Instead, it produces nitrous oxide (N_2O). The reaction can be summarized as:
   • 4Zn + 10HNO_3 (dil.) \rightarrow 4Zn(NO_3)_2 + 5H_2O + N_2O\uparrow
2. When zinc reacts with concentrated nitric acid, the strong oxidizing nature of the acid leads to the formation of nitrogen dioxide (NO_2). The reaction proceeds as follows:
   • Zn + 4HNO_3 (conc.) \rightarrow Zn(NO_3)_2 + 2H_2O + 2NO_2\uparrow

Thus, for the given question, when zinc reacts with:

• Dilute nitric acid, N_2O is produced.
• Concentrated nitric acid, NO_2 is produced.

Hence, the correct answer is: $N_2O$ (with dilute nitric acid) and $NO_2$ (with concentrated nitric acid).