Match List I with List II and select the correct answer using the code given below the Lists : List I (Chemical process) List II (Reaction) A. Electrolysis of water 1. Double displacement reaction 2. Combination reaction C. Iron nail immersed in copper sulphate solution 3. Decomposition reaction 4. Displacement reaction D. Addition of barium chloride solution to aluminium sulphate solution Code :

The chemical reactions are classified based on the nature of the transformation:

• A. Electrolysis of water (3): This is a Decomposition reaction where electrical energy breaks down water molecules into hydrogen and oxygen gases (2H2O → 2H2 + O2).
• B. Burning of magnesium ribbon (2): This is a Combination reaction. Magnesium reacts with atmospheric oxygen to form a single product, magnesium oxide (2Mg + O2 → 2MgO).
• C. Iron nail in copper sulphate (4): This is a Displacement reaction. Iron, being more reactive than copper, displaces copper from its salt solution (Fe + CuSO4 → FeSO4 + Cu).
• D. Barium chloride and aluminium sulphate (1): This is a Double displacement reaction. The ions of the two reactants exchange partners to form barium sulphate and aluminium chloride (3BaCl2 + Al2(SO4)3 → 3BaSO4 + 2AlCl3).

Thus, the correct sequence is 3-2-4-1, matching Option C.