Correct Option (D):
- A. Blue vitriol is chemically known as copper sulphate (CuSO₄·5H₂O).
- B. Epsom salt is magnesium sulphate (MgSO₄·7H₂O).
- C. Baking soda is sodium bicarbonate (NaHCO₃).
- D. Caustic soda is sodium hydroxide (NaOH).
The correct matching sequence is A-4, B-3, C-1, D-2, which corresponds to the code 4312.
Incorrect Options
Options (1), (2), and (3) are incorrect as they present different pairings for the substances listed in List I with their chemical names in List II. Each of these options contains at least one mismatch with the correct chemical identities and formulas of the compounds.