JEE Main · 2025 · 04 Apr 2025 · Shift 1 · Some Basic Concepts of Chemistry

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Fortification of food with iron is done using FeSO₄·7H₂O. The mass in grams of the FeSO₄·7H₂O required to achieve 12 ppm of iron in 150 kg of wheat is ____ (Nearest integer)
[Given: Molar mass of Fe, S and O respectively are 56, 32 and 16 g mol⁻¹]

Answer: 9

Solution

A level of

12 ppm

of iron in

150 kg

of wheat means

12 mg

of iron per kilogram, so the iron needed is

12 \times 150 = 1800 mg = 1.8 g

. The molar mass of

FeS O_{4} \cdot 7 H_{2} O

56 + 32 + 4 (16) + 7 (18) = 278 g mo l^{- 1}

, and since each formula unit carries one iron atom, the mass of the hydrate required is

1.8 \times \frac{278}{56} = 8.94 g

, which to the nearest integer is

9 g

JEE Main · 2025 · 04 Apr 2025 · Shift 1 · Integer answer

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