Some crystals of ferrous sulphate were dissolved in distilled water. The colour of the solution obtained was

According to the NCERT textbook (Activity 1.5), ferrous sulphate crystals ($FeSO_4 \cdot 7H_2O$) have a characteristic green colour. When these crystals are dissolved in distilled water, they dissociate to form hydrated $Fe^{2+}$ ions, which impart a characteristic pale green colour to the solution.

• Option A (dark green): Incorrect. The solution is quite light or pale green, not dark green.
• Option B (pale green): Correct. This is the standard colour of a freshly prepared aqueous solution of ferrous sulphate.
• Option C (light blue): Incorrect. Light blue is the colour of an aqueous solution of copper sulphate ($CuSO_4 \cdot 5H_2O$).
• Option D (dark blue): Incorrect. Dark blue is not associated with ferrous sulphate solutions.