What is the maximum concentration of equimolar solutions of ferrous sulphate and sodium sulphide so that when mixed in equal volumes, there is no precipitation of iron sulphide? (For iron sulphide, `K_(sp)=6.3xx10^(-18))`.

Explanation

To solve the problem, we need to find the maximum concentration of equimolar solutions of ferrous sulfate (FeSO4) and sodium sulfide (Na2S) such that when mixed in equal volumes, there is no precipitation of iron sulfide (FeS). We will use the solubility product constant (Ksp) of FeS, which is given as \( K_{sp} = 6.3 \times 10^{-18} \).

### Step-by-step Solution:

1. **Define the Concentration**:
Let the concentration of both FeSO4 and Na2S be \( y \) mol/L.

2. **Mixing the Solutions**:
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