In the reaction given below identify the species undergoing oxidation and reduction :
(i) `CH_(4)(g)+2O_(2)(g)rarr CO_(2)(g)+2H_(2)O(l)`
(ii)`H_(2)S(g)+O_(2)(g)rarr2S(s)+2H_(2)O(l)`
(iii)`CH_(2)=CH_(2)(g)+H_(2)(g)rarrH_(3)C-CH_(3)(g)`
(iv)`HgO(s)rarr2Hg(l)+O_(2)(g)`
(v)`Mg(s)+S(s)rarr MgS(s)`

Explanation

To identify the species undergoing oxidation and reduction in the given reactions, we need to analyze the changes in oxidation states of the elements involved in each reaction. Here's a step-by-step solution for each reaction:

### (i) CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(l)

1. **Assign Oxidation States:**
- In CH₄, C is -4 and H is +1.
- In O₂, O is 0.
- In CO₂, C is +4 and O is -2.
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