(A) Kieselguhr (Diatomaceous earth) ⟶ Used for filtration (it is a fine, porous, siliceous material). - So, (A)⟶( III ) Filtration plants (B) Silica gel ⟶ Used in chromatography as an adsorbent. So, (B)⟶(I) Chromatographic material (C) ZSM-5 (a type of zeolite catalyst) ⟶ Used to convert alcohol directly into gasoline (in petrochemical industry). So, (C) ⟶ (IV) To convert alcohol directly into gasoline (D) Hydrated zeolites ⟶ Used in softening of hard water (by ion exchange). - So, (D) ⟶ (II) Softening of hard water Now, putting it all together: (A)-III, (B)-I, (C)-IV, (D)-II Correct Answer: Option D
