Reaction between which of the following two reactants will produce hydrogen gas?
Magnesium and hydrochloric acid
Copper and dilute nitric acid
Calcium carbonate and hydrochloric acid
Zinc and nitric acid
Answer is Right!
Answer is Wrong!
This question was previously asked in
UPSC CDS-2 – 2018
Option B (Copper and dilute nitric acid): Nitric acid is an oxidizing acid, and while it reacts with copper, it typically produces nitrogen oxides rather than hydrogen gas.
Option C (Calcium carbonate and hydrochloric acid): This produces carbon dioxide gas (CO₂), water, and calcium chloride (CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂).
Option D (Zinc and nitric acid): Similar to copper, zinc reacts with nitric acid to produce zinc nitrate and nitrogen oxides (or ammonium nitrate with very dilute acid), not primarily hydrogen gas.