Which metal bicarbonates does not exist in solid state?
(i)`LiHCO_(3)` (ii)`Ca(HCO_(3))_(2)` (iii)`Zn(HCO_(3))_(2)` (iv)`CaS_(2)O_(3)`

Options

A. (i)
B. (ii)
C. (iii)
D. (iv)

Explanation

To determine which metal bicarbonate does not exist in solid state, we will analyze each of the given options step by step.

### Step 1: Understanding Bicarbonates
Bicarbonates, also known as hydrogen carbonates, are salts that contain the bicarbonate ion (HCO₃⁻). They are typically formed from alkali and alkaline earth metals.

### Step 2: Analyze Each Option
1. **LiHCO₃ (Lithium Bicarbonate)**:
- Lithium is an alkali metal. However, lithium bicarbonate is known to be unstable and does not exist in solid form at room temperature. It tends to decompose into lithium carbonate and carbon dioxide when heated.

2. **Ca(HCO₃)₂ (Calcium Bicarbonate)**:
- Calcium bicarbonate is a salt of an alkaline earth metal. It is soluble in water, but it can exist in solid form as a precipitate under certain conditions. However, it is not stable in solid form and tends to decompose into calcium carbonate and carbon dioxide.

3. **Zn(HCO₃)₂ (Zinc Bicarbonate)**:
- Zinc bicarbonate can exist in solid form. It is stable and does not decompose easily at room temperature.

4. **CaS₂O₃ (Calcium Thiosulfate)**:
- This is not a bicarbonate but a thiosulfate. It can exist in solid form, but it is not relevant to the question about bicarbonates.

### Step 3: Conclusion
Based on the analysis, the bicarbonate that does not exist in solid state is **LiHCO₃ (Lithium Bicarbonate)**.

### Final Answer
The metal bicarbonate that does not exist in solid state is **(i) LiHCO₃**.

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