The colour of an aqueous solution of zinc sulphate as observed in the laboratory is:

An aqueous solution of zinc sulphate ($ZnSO_4$) is completely colourless.

• Option 1 (Green) is incorrect because light green is the characteristic colour of an aqueous solution of ferrous sulphate ($FeSO_4$).
• Option 2 (Yellow) is incorrect because yellow is not the colour of zinc sulphate; some ferric ($Fe^{3+}$) salts form yellowish solutions.
• Option 3 (Blue) is incorrect because blue is the characteristic colour of an aqueous copper sulphate ($CuSO_4$) solution.