`NaCl` of `95%` purity is used to prepare salt cake `(Na_(2)SO_(4))` by the reaction,
`2NaCl+H_(2)SO_(4)rarrNa_(2)SO_(4)+2HCl.`
If the product `(Na_(2)SO_(4))` is only `85%` pure, what weight of `NaCl` is used up in producing 1 kg of the impure salt cake ?

Explanation

To find the weight of NaCl used to produce 1 kg of impure salt cake (Na₂SO₄), we can follow these steps:

### Step 1: Determine the weight of pure Na₂SO₄ produced
Given that the Na₂SO₄ produced is only 85% pure, we can calculate the weight of pure Na₂SO₄ in 1 kg of the impure product.

\[ \text{Weight of pure Na}_2\text{SO}_4 = \text{Weight of impure Na}_2\text{SO}_4 \times \text{Purity} \]
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