Step 1: Calculate the mass of iron required

12 ppm means 12 mg of iron per kg of wheat.

Step 2: Calculate total iron needed for 150 kg wheat

Iron required = 12 × 150 = 1800 mg = 1.8 g

Step 3: Calculate molar mass of FeSO₄·7H₂O

FeSO₄ = 56 + 32 + (4 × 16) = 152 g mol⁻¹
7H₂O = 7 × 18 = 126 g mol⁻¹
Total molar mass = 152 + 126 = 278 g mol⁻¹

Step 4: Calculate fraction of iron in FeSO₄·7H₂O

Fraction of Fe = 56 / 278

Step 5: Calculate mass of FeSO₄·7H₂O required

Required mass = 1.8 × (278 / 56) ≈ 8.93 g