Question

Which gas is evolved when zinc reacts with dilute hydrochloric acid?

• A. Oxygen
• B. Chlorine
• C. Hydrogen
• D. Nitrogen

Hint:

You can test for Hydrogen gas by bringing a burning splinter near the mouth of the test tube—it will burn with a characteristic "pop" sound!

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Active metals (metals above hydrogen in the reactivity series) react with dilute mineral acids to produce a salt and evolve hydrogen gas.
Step 2: Detailed Explanation:
1. Zinc (\(Zn\)) is more reactive than hydrogen.
2. When zinc metal is added to dilute hydrochloric acid (\(HCl\)), a displacement (redox) reaction occurs.
3. Zinc atoms lose electrons to form \(Zn^{2+}\) ions, and Hydrogen ions from the acid gain electrons to form \(H_2\) gas.
4. Chemical Equation: \[ Zn(s) + 2HCl(aq) \rightarrow ZnCl_2(aq) + H_2(g) \uparrow \]
Step 3: Final Answer:
The gas evolved during the reaction of zinc with dilute \(HCl\) is hydrogen.