Question

Hydrogen gas is not evolved when zinc metal reacts with dilute HNO. Give reason .​

Answer 1

Answer:

hno3 is strong oxidising agent it oxidise H2 and covert it into h2O

Answer 2

Correction : The question should be " Hydrogen gas is not evolved when zinc metal reacts with dilute HNO₃. Give reason".

Hydrogen gas is not evolved when zinc metal reacts with dilute HNO₃, because dilute HNO₃ is a strong oxidizing agent.

• An oxidizing agent is a chemical substance that oxidizes another substance by getting reduced itself.

• Action of dilute HNO₃ on zinc immediately oxidizes the hydrogen gas generated in the process into water.

• HNO₃ itself gets reduced to nitrogen oxides like NO or NO₂, depending upon the moles of HNO₃ used.

• Zn + 4 dil. HNO₃  → Zn(NO₃)₂ + 2NO₂ + 2H₂O

• 3Zn + 8 dil. HNO₃ → 3Zn(NO₃)₂ + 2NO + 4H₂O

• Thus, dilute HNO₃ gives water instead of hydrogen, and is, therefore, not used in the preparation of hydrogen gas from zinc.