Match the compounds listed in colomn-I with the related uses/particulars listed in column-II.
`{:("Column I","Column II"),((A)"Calcium hypochlorite",(p)"Used as air purifier in submarine"),((B)"Calcium suphate hemi hydrate",(q)"Used for 'softening' water"),((C )"Potassium super oxide",(r)"A constituent of bleaching powder" ),((D)"Calcium oxide",(s)"Plaster of Paris"),(,(t)"Used in preparation of sodium hydroxide."):}`

Explanation

To match the compounds listed in Column I with their related uses or particulars in Column II, we will analyze each compound and its potential uses step by step.

### Step 1: Analyze Calcium Hypochlorite (A)
- **Calcium Hypochlorite** is primarily known as a bleaching agent and is a constituent of bleaching powder.
- **Matching Options**:
- (p) Used as air purifier in submarine - **False**
- (q) Used for 'softening' water - **False**
- (r) A constituent of bleaching powder - **True**
- (s) Plaster of Paris - **False**
- (t) Used in preparation of sodium hydroxide - **False**

**Conclusion**: A matches with **R**.

### Step 2: Analyze Calcium Sulphate Hemihydrate (B)
- **Calcium Sulphate Hemihydrate** is commonly known as Plaster of Paris.
- **Matching Options**:
- (p) Used as air purifier in submarine - **False**
- (q) Used for 'softening' water - **False**
- (r) A constituent of bleaching powder - **False**
- (s) Plaster of Paris - **True**
- (t) Used in preparation of sodium hydroxide - **False**

**Conclusion**: B matches with **S**.

### Step 3: Analyze Potassium Superoxide (C)
- **Potassium Superoxide** (KO2) is used for purifying air in submarines by absorbing carbon dioxide and releasing oxygen.
- **Matching Options**:
- (p) Used as air purifier in submarine - **True**
- (q) Used for 'softening' water - **False**
- (r) A constituent of bleaching powder - **False**
- (s) Plaster of Paris - **False**
- (t) Used in preparation of sodium hydroxide - **False**

**Conclusion**: C matches with **P**.

### Step 4: Analyze Calcium Oxide (D)
- **Calcium Oxide** (CaO) is used for softening water and also in the preparation of sodium hydroxide.
- **Matching Options**:
- (p) Used as air purifier in submarine - **False**
- (q) Used for 'softening' water - **True**
- (r) A constituent of bleaching powder - **False**
- (s) Plaster of Paris - **False**
- (t) Used in preparation of sodium hydroxide - **True**

**Conclusion**: D matches with **Q** and **T**.

### Final Matching
- A → R (Calcium hypochlorite is a constituent of bleaching powder)
- B → S (Calcium sulfate hemihydrate is Plaster of Paris)
- C → P (Potassium superoxide is used as an air purifier in submarines)
- D → Q and T (Calcium oxide is used for softening water and in the preparation of sodium hydroxide)

### Summary of Matches
- A - R
- B - S
- C - P
- D - Q, T

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