Match List - I with List - II and select the correct answer from the codes given below the lists : List – I (Substance) A) Blue Vitriol B) Eosin C) Silver iodide D) Zinc phosphide List – II (Use) 1) Artificial rain 2) Fungicide 3) Red ink 4) Rodenticide Codes:

Work through the pairs one at a time. Blue vitriol is copper sulphate pentahydrate (CuSO4·5H2O). Its main use is as a fungicide, and it is the copper source in the Bordeaux mixture used against crop fungal diseases, so A matches 2. Eosin is a xanthene dye that gives a red colour, used in red ink and as a stain, so B matches 3. Silver iodide has a hexagonal crystal structure close to ice, so it is seeded into clouds to induce precipitation, which is artificial rain (1). Zinc phosphide is a highly toxic compound used as a rodenticide (4).

The correct set is A-2, B-3, C-1, D-4, which is option C.

• Option A pairs silver iodide with rodenticide and zinc phosphide with artificial rain. Both are wrong.
• Option B pairs eosin with artificial rain and silver iodide with red ink. Both are wrong.
• Option D pairs eosin with rodenticide and zinc phosphide with red ink. Both are wrong.

Mains angle: silver iodide cloud seeding links to water resource and drought management discussions in Geography and Environment.

Trap: students often guess between A and C without checking the strongest pairs. Fix zinc phosphide with rodenticide and silver iodide with artificial rain first. Those two alone eliminate A, B and D.