Microcosmic salt reacts with coloured ions to form characteristic bead which is due to formation

Answer

To solve the question regarding the reaction of microcosmic salt with colored ions to form characteristic beads, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Microcosmic Salt**:
- Microcosmic salt is chemically known as sodium ammonium hydrogen phosphate (NaNH4HPO4). It is commonly used in qualitative inorganic analysis.

2. **Reaction with Colored Ions**:
- When microcosmic salt is heated with colored metal ions (like copper ions), it forms a characteristic bead. This is due to the formation of a metal phosphate.

3. **Formation of Sodium Metaphosphate**:
- Upon heating, microcosmic salt decomposes to form sodium metaphosphate (NaPO3). The reaction can be represented as:
\[ \text{NaNH}_4\text{HPO}_4 \rightarrow \text{NaPO}_3 + \text{NH}_3 + \text{H}_2\text{O} \]

4. **Reaction with Copper Oxide**:
- The sodium metaphosphate then reacts with copper oxide (CuO) to form sodium copper phosphate (NaCuPO4), which is a blue compound. The reaction can be represented as:
\[ \text{NaPO}_3 + \text{CuO} \rightarrow \text{NaCuPO}_4 \]

5. **Characteristic Bead Formation**:
- The resulting sodium copper phosphate (NaCuPO4) forms a blue bead when heated in the flame. This blue color is characteristic of copper ions and indicates the presence of copper in the sample.

6. **Conclusion**:
- The characteristic bead formed when microcosmic salt reacts with colored ions is primarily due to the formation of metal phosphates, specifically sodium copper phosphate in the case of copper ions.