`Ca(s)+H_(2)O(l) overset(R.T.)toCa(OH)_(2)+H_(2)uarr`

Options

A. For disproportionation reaction.
B. For comproportionation reaction.
C. For either intermolecular redox reaction or displacement reaction
D. For either thermal combination redox reaction or thermal decomposition redox reaction.

Answer

To analyze the given reaction \( \text{Ca}(s) + \text{H}_2\text{O}(l) \overset{R.T.}{\rightarrow} \text{Ca(OH)}_2 + \text{H}_2 \uparrow \), we need to determine the type of reaction it represents. Let's break it down step by step.

### Step 1: Identify the Reactants and Products
The reactants are calcium (Ca) in solid form and water (H₂O) in liquid form. The products are calcium hydroxide (Ca(OH)₂) and hydrogen gas (H₂).

### Step 2: Determine Oxidation States
- **Calcium (Ca)**: In its elemental form, the oxidation state is 0.
- **Hydrogen in Water (H₂O)**: The oxidation state of hydrogen is +1.
- **Calcium in Calcium Hydroxide (Ca(OH)₂)**: The oxidation state of calcium is +2.
- **Hydrogen in Hydrogen Gas (H₂)**: The oxidation state of hydrogen is 0.

### Step 3: Analyze Changes in Oxidation States
- Calcium changes from 0 (in Ca) to +2 (in Ca(OH)₂), indicating that it is oxidized.
- Hydrogen changes from +1 (in H₂O) to 0 (in H₂), indicating that it is reduced.

### Step 4: Classify the Reaction
Since we have one species (calcium) being oxidized and another species (hydrogen) being reduced, this reaction is classified as a **redox reaction**.

### Step 5: Determine the Type of Redox Reaction
This reaction does not involve the same element being oxidized and reduced (which would indicate a disproportionation or comproportionation reaction). Instead, it involves different elements undergoing oxidation and reduction. Therefore, it is an **intermolecular redox reaction**.

### Conclusion
The type of reaction is an **intermolecular redox reaction**.

### Final Answer
The answer is **C: Intermolecular redox reaction**.

---