(i) Identify the compounds A and B.
(1) `C_(6)H_(5)COONa+NaOH overset(CaO)to A underset("Conc." H_(2)SO_(4))overset("Conc." HNO_(3))to B`
(2) `C_(2)H_(6) underset(hv)overset(Br_(2))to A underset("heat")overset("Alc koH")toB`
(ii) State an appropriate chemical test used to distinguish between the following pairs of compounds:
(1) Ethene and Ethyne
(2) But-1-ene and but-2-ene.

Explanation

To solve the given question, we need to identify the compounds A and B from the provided reactions and then state appropriate chemical tests to distinguish between the specified pairs of compounds.

### Part (i): Identify the compounds A and B

**Step 1: Analyze the first reaction**
- The first reaction involves sodium benzoate (`C6H5COONa`) reacting with sodium hydroxide (`NaOH`) in the presence of calcium oxide (`CaO`). This reaction leads to decarboxylation.
- The product A formed from this reaction is benzene (`C6H6`).

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