Question

Which one of the following is not formed when metal carbonate reacts with dilute acid?

• A. Salt
• B. Carbon dioxide
• C. Hydrogen
• D. Water

Answer 1

The Correct Option is C

To determine which substance is not formed when a metal carbonate reacts with dilute acid, we need to analyze the chemical reaction involved.

1. Understanding the Reaction:
When a metal carbonate ($\text{MCO}_3$, where $\text{M}$ is a metal) reacts with a dilute acid (such as hydrochloric acid, $\text{HCl}$), the general reaction can be represented as:

$$ \text{MCO}_3 + 2\text{HCl} \rightarrow \text{MCl}_2 + \text{H}_2\text{O} + \text{CO}_2 $$

This reaction produces three main products:

• Salt: The metal chloride ($\text{MCl}_2$) is formed as a salt.
• Water: Water ($\text{H}_2\text{O}$) is produced as a byproduct.
• Carbon Dioxide: Carbon dioxide ($\text{CO}_2$) gas is released.

2. Identifying the Missing Product:
From the reaction, it is clear that hydrogen gas ($\text{H}_2$) is not produced. The hydrogen ions from the acid combine with the carbonate ion to form water and carbon dioxide, but no hydrogen gas is liberated.

3. Conclusion:
The substance that is not formed when a metal carbonate reacts with dilute acid is hydrogen gas.

Final Answer:
$ {\text{Hydrogen}} $