Reaction between which of the following two reactants will produce hydrogen gas?
[amp_mcq option1=”Magnesium and hydrochloric acid” option2=”Copper and dilute nitric acid” option3=”Calcium carbonate and hydrochloric acid” option4=”Zinc and nitric acid” correct=”option1″]
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.