Which of the following is not a water absorber and dehydrating substance

Options

A. Silica gel
B. `P_(2)O_(5)`
C. Conc.`H_(2)SO_(4)`
D. Aqueous `CaCl_(2)`

Explanation

To determine which of the following substances is not a water absorber and dehydrating agent, let's analyze each option step by step.

### Step 1: Analyze Silica Gel
- **Silica Gel** is a porous form of silicon dioxide (SiO2) that has a high surface area.
- It is commonly used as a desiccant because it can absorb moisture from the air.
- **Conclusion**: Silica gel is a water absorber and dehydrating substance.

### Step 2: Analyze P2O5
- **P2O5** (phosphorus pentoxide) is known for its strong dehydrating properties.
- When it comes into contact with water, it forms phosphoric acid (H3PO4) and effectively absorbs water vapor.
- **Conclusion**: P2O5 is a water absorber and dehydrating substance.

### Step 3: Analyze Concentrated H2SO4
- **Concentrated H2SO4** (sulfuric acid) is a strong dehydrating agent.
- It has the ability to absorb water from other substances and can even dehydrate organic compounds.
- **Conclusion**: Concentrated H2SO4 is a water absorber and dehydrating substance.

### Step 4: Analyze Aqueous CaCl2
- **Aqueous CaCl2** refers to calcium chloride dissolved in water.
- While anhydrous CaCl2 is known for its dehydrating properties, when it is in an aqueous solution, it is already mixed with water and cannot act as a dehydrating agent.
- **Conclusion**: Aqueous CaCl2 is not a dehydrating agent.

### Final Answer
The substance that is **not** a water absorber and dehydrating substance is **Aqueous CaCl2**.

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