Question

A solution reacts with marble chips to produce a gas which turns lime water milky. The solution contains:
(A) $N{{a}_{2}}S{{O}_{4}}$
(B) $CaS{{O}_{4}}$
(C) ${{H}_{2}}S{{O}_{4}}$
(D)${{K}_{2}}S{{O}_{4}}$

Answer 1

Hint: The lime water will turn milky only when the lime water is passed through carbon dioxide. So the marble chips react with acid for the evolution of carbon dioxide.

Complete step by step solution:
Lime water has a formula of $Ca{{(OH)}_{2}}$, it is produced when calcium hydroxide which is sparingly soluble in water. When the calcium hydroxide is dissolved in water, it produces an alkaline solution that is known as lime water.
The calcium hydroxide turns milky because of the formation of calcium carbonate which has a formula $CaC{{O}_{3}}$, this is because the calcium hydroxide is treated with carbon dioxide gas. The reaction is:
$Ca{{(OH)}_{2}}+C{{O}_{2}}\to CaC{{O}_{3}}+{{H}_{2}}O$
Marble chips are the substances that have the formula $CaC{{O}_{3}}$.
So when marble chips are reacted with a solution that produces a gas that turns the lime water milky. This means that the evolved gas is carbon dioxide.
So, the carbonates produce carbon dioxide gas only when it is treated with an acid.
Therefore, from the above options, we have the option (C)- ${{H}_{2}}S{{O}_{4}}$, which is an acid.
So, when the marble chips are reacted with sulfuric acid then it produces calcium sulfate, carbon dioxide, and water. The reaction is given below:
$CaC{{O}_{3}}+{{H}_{2}}S{{O}_{4}}\to CaS{{O}_{4}}+C{{O}_{2}}+{{H}_{2}}O$
So, this carbon dioxide will turn the lime water milky.

Therefore, the correct answer uses an option (C)- ${{H}_{2}}S{{O}_{4}}$.

Note: $CaO$is called lime and when it is treated with water, it forms lime water.
$CaO+{{H}_{2}}O\to Ca{{(OH)}_{2}}$.
When the lime is reacted with sulfur dioxide it forms calcium sulfite.
$CaO+S{{O}_{2}}\to CaS{{O}_{3}}$.