Reaction between which of the following two reactants will produce hydrogen gas?

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Q: 3 (CDS-II/2018)
Reaction between which of the following two reactants will produce hydrogen gas?

question_subject: 

Science

question_exam: 

CDS-II

stats: 

0,28,32,28,4,24,4

keywords: 

{'hydrogen gas': [0, 0, 1, 2], 'reactants': [0, 0, 0, 3], 'reaction': [1, 0, 5, 18], 'nitric acid': [0, 0, 0, 2], 'hydrochloric acid': [1, 0, 3, 0], 'magnesium': [1, 0, 2, 3], 'calcium carbonate': [0, 0, 1, 4], 'zinc': [1, 0, 0, 2], 'copper': [1, 0, 1, 1], 'dilute': [0, 0, 0, 4]}

The correct answer is option 1, which is the reaction between magnesium and hydrochloric acid.

Let`s analyze each option to understand why it is the correct answer and why the other options are not:

Option 1: Magnesium and hydrochloric acid

When magnesium reacts with hydrochloric acid, it undergoes a single displacement reaction, replacing hydrogen in the acid. This reaction produces magnesium chloride and hydrogen gas.

Option 2: Copper and dilute nitric acid

Copper does not react with dilute nitric acid. Nitric acid does not have a strong oxidizing nature, and therefore, it does not displace copper and produce hydrogen gas.

Option 3: Calcium carbonate and hydrochloric acid

The reaction between calcium carbonate and hydrochloric acid does produce a gas but not hydrogen. It produces carbon dioxide gas. The equation for this reaction is calcium carbonate + hydrochloric acid [REPLACEMENT] calcium chloride + water + carbon dioxide.

Option 4: Zinc and nitric acid

Zinc reacts with nitric acid to form nitrogen dioxide gas, not hydrogen gas. The equation for this reaction is zinc + nitric acid [REPLACEMENT] zinc nitrate + nitrogen dioxide + water.

Therefore, based on the analysis, option 1, the reaction between