Hydrous ferrous sulphate crystals are heated in a boiling tube for few seconds. Water droplets are seen in the inner sides of test tube and the colour of the crystals changes. On continuous heating a colourless gas X with smell of burning sulphur is evolved and a residue Y is obtained.
Write the balanced chemical equation for the above reaction.

Explanation

To solve the problem, we need to write the balanced chemical equation for the reaction that occurs when hydrous ferrous sulfate (FeSO4·7H2O) is heated. Here's a step-by-step breakdown of the solution:

### Step 1: Identify the Reactants
The main reactant is hydrous ferrous sulfate, which can be represented as:
\[ \text{FeSO}_4 \cdot 7\text{H}_2\text{O} \]

### Step 2: Understand the Reaction
When hydrous ferrous sulfate is heated, it decomposes. The water of hydration is released first, which is why we see water droplets on the inner sides of the test tube. The decomposition leads to the formation of anhydrous ferrous sulfate (FeSO4) and the release of water vapor.
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