Nitrogen dioxide turns acidified ferrous sulphate solution _____ [black/brown]

Explanation

To solve the question "Nitrogen dioxide turns acidified ferrous sulphate solution _____ [black/brown]", we can follow these steps:

### Step 1: Identify the reactants
The reactants in this scenario are nitrogen dioxide (NO2) and acidified ferrous sulphate (FeSO4). The ferrous sulphate contains Fe²⁺ ions in solution.

**Hint:** Look for the chemical species involved in the reaction.

### Step 2: Understand the reaction conditions
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