Nitrates of all the metals except mercury and bismuth are:

Options

A. coloured
B. unstable
C. soluble in water
D. insoluble in water

Answer

To solve the question regarding the solubility of nitrates of metals, we will analyze the properties of nitrates and their behavior in water.

### Step-by-Step Solution:

1. **Understanding Nitrates**: Nitrates are salts formed from nitric acid (HNO3) and a metal. They generally have the formula M(NO3)n, where M is the metal and n is the number of nitrate ions.

2. **Solubility of Nitrates**: Most metal nitrates are known to be soluble in water. This is due to the fact that the energy released during the solvation process (when water molecules surround and interact with the ions) is greater than the energy required to break the ionic bonds in the solid nitrate.

3. **Exceptions**: The question specifies exceptions to this rule. The nitrates of mercury (Hg) and bismuth (Bi) are not soluble in water. This is an important detail to note.

4. **Conclusion**: Therefore, the nitrates of all metals except mercury and bismuth are soluble in water.

### Final Answer:
Nitrates of all metals except mercury and bismuth are soluble in water.

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