In the reaction `2 KCIO_(3) rarr 2KCI+3 O_(2)` the element which has been oxidised is …………….and the element which has been reduced is ……………

Answer

To determine which element is oxidized and which is reduced in the reaction \(2 \text{KClO}_3 \rightarrow 2 \text{KCl} + 3 \text{O}_2\), we need to analyze the oxidation states of the elements involved in the reaction.

### Step-by-Step Solution:

1. **Identify the Reactants and Products**:
We have potassium chlorate (\(KClO_3\)) as the reactant and potassium chloride (\(KCl\)) and oxygen gas (\(O_2\)) as the products.

2. **Assign Oxidation States**:
- In \(KClO_3\):
- Potassium (K) has an oxidation state of +1.
- Oxygen (O) has an oxidation state of -2.
- Let the oxidation state of Chlorine (Cl) be \(x\). The equation for the oxidation states in \(KClO_3\) is:
\[ +1 + x + 3(-2) = 0 \implies +1 + x - 6 = 0 \implies x = +5 \]
- Therefore, in \(KClO_3\), K is +1, Cl is +5, and O is -2.

- In \(KCl\):
- K is +1.
- Cl is -1.

- In \(O_2\):
- Each O has an oxidation state of 0 (as it is in its elemental form).

3. **Determine Changes in Oxidation States**:
- For Chlorine (Cl):
- Changes from +5 in \(KClO_3\) to -1 in \(KCl\).
- This is a decrease in oxidation state, indicating that Cl is reduced.

- For Oxygen (O):
- Changes from -2 in \(KClO_3\) to 0 in \(O_2\).
- This is an increase in oxidation state, indicating that O is oxidized.

4. **Conclusion**:
- The element that has been oxidized is **Oxygen (O)**.
- The element that has been reduced is **Chlorine (Cl)**.

### Final Answer:
- The element which has been oxidized is **Oxygen (O)** and the element which has been reduced is **Chlorine (Cl)**.