When 1 mole of a substance `(X)` was treated with an excess of water, 2 moles of readily combustible gas were produced along with solution which when reacted with `CO_(2)` gas produced a white turbidity. The substance `(X)` could be

Options

A. `Ca`
B. `CaH_(2)`
C. `Ca(OH)_(2)`
D. `Ca(NO_(3))_(2)`

Answer

To solve the problem step by step, we can analyze the information given in the question:

### Step 1: Analyze the reaction with water
The question states that when 1 mole of a substance (X) is treated with excess water, it produces 2 moles of a readily combustible gas.

**Hint:** Consider substances that can react with water to produce hydrogen gas, which is a readily combustible gas.

### Step 2: Identify potential candidates for substance (X)
We need to consider various substances that could fit the description. The options provided are likely to include metals or metal hydrides that react with water.

**Hint:** Focus on metal hydrides or alkali metals that are known to react vigorously with water.

### Step 3: Evaluate Calcium (Ca)
When calcium (Ca) reacts with water, it forms calcium hydroxide (Ca(OH)₂) and hydrogen gas (H₂). The reaction is:
\[ \text{Ca} + 2\text{H}_2\text{O} \rightarrow \text{Ca(OH)}_2 + \text{H}_2 \]
This produces only 1 mole of H₂ gas, not 2 moles, so calcium is not the correct substance.

**Hint:** Check the stoichiometry of the reaction to see how many moles of gas are produced.

### Step 4: Evaluate Calcium Hydride (CaH₂)
Calcium hydride (CaH₂) reacts with water to produce calcium hydroxide and hydrogen gas:
\[ \text{CaH}_2 + 2\text{H}_2\text{O} \rightarrow \text{Ca(OH)}_2 + 2\text{H}_2 \]
This reaction produces 2 moles of hydrogen gas, which fits the requirement.

**Hint:** Ensure that the number of moles of gas produced matches the question's criteria.

### Step 5: Check the solution with CO₂
The question also states that the solution formed reacts with CO₂ to produce white turbidity. Calcium hydroxide reacts with CO₂ to form calcium carbonate (CaCO₃), which is insoluble in water and gives a milky appearance:
\[ \text{Ca(OH)}_2 + \text{CO}_2 \rightarrow \text{CaCO}_3 + \text{H}_2\text{O} \]
This confirms that calcium hydride is a suitable candidate.

**Hint:** Look for reactions that produce precipitates or turbidity when CO₂ is introduced.

### Step 6: Evaluate Calcium Hydroxide (Ca(OH)₂)
Calcium hydroxide itself does not produce any combustible gas when treated with water, so it cannot be substance (X).

**Hint:** Consider the properties of the compounds to determine if they can produce the required products.

### Step 7: Evaluate Calcium Nitrate (Ca(NO₃)₂)
Calcium nitrate does not produce any combustible gas when treated with water. It mainly dissolves in water without producing additional gases.

**Hint:** Analyze the chemical behavior of nitrates in water.

### Conclusion
The only substance that meets all the criteria is calcium hydride (CaH₂). Therefore, the answer to the question is:

**Substance (X) is Calcium Hydride (CaH₂).**