`A+dil.H_(2)SO_(4)overset(Delta)to gas(B)`. Gas(B) turns `K_(2)Cr_(2)O_(7)//H` solution green.
Aq. solution of `A+BaCl_(2)to White ppt.(C)`Filtrate after removing (C) + Br_(2) ​water ⟶whiteppt(C). Here (A), (B) and (C) are
Identify(A),(B) and(C).

Explanation

To solve the problem, we need to identify the substances A, B, and C based on the given reactions and observations. Let's break down the information step by step.

### Step 1: Identify Gas B
The problem states that gas (B) is produced when substance (A) is treated with dilute sulfuric acid (H₂SO₄) and that gas (B) turns potassium dichromate (K₂Cr₂O₇) solution green.

1. **Observation**: The green color indicates a reduction reaction, where Cr(VI) from K₂Cr₂O₇ is reduced to Cr(III).
2. **Conclusion**: A common gas that can reduce Cr(VI) to Cr(III) is hydrogen sulfide (H₂S) or sulfur dioxide (SO₂). However, since we are looking for a substance that can react with dilute sulfuric acid to produce a gas, we can conclude that (A) is likely to be a sulfide, specifically hydrogen sulfide (H₂S).

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