Match List-I with List-II List-I (Items) List-II (Properties) (A) Pri…

The correct answer is Option (1) → (A)-(IV), (B)-(III), (C)-(I), (D)-(II)

List-I (Items)	List-II (Properties)
(A) Primary batteries	(IV) Mercury cell is used in hearing aids.
(B) Secondary batteries	(III) Large number of charging/discharging and long-lasting
(C) Fuel Cells	(I) Pollution free energy converter
(D) Corrosion	(II) Takes place in the presence of air, moisture and $H^+$

(A) Primary Batteries $\rightarrow$ (IV) Mercury cell is used in hearing aids: Primary batteries are non-rechargeable cells where the reaction occurs only once. A mercury cell is a common primary battery that provides a very stable voltage (1.35 V) throughout its life, making it ideal for low-current devices like hearing aids, watches, and cameras.

(B) Secondary Batteries $\rightarrow$ (III) Large number of charging/discharging and long-lasting: Secondary batteries (like Lead-acid batteries or Lithium-ion batteries) are rechargeable. They are designed to undergo a large number of charging and discharging cycles by reversing the chemical reaction through an external electrical source.

(C) Fuel Cells $\rightarrow$ (I) Pollution free energy converter: Fuel cells (such as the $H_2-O_2$ fuel cell) convert the chemical energy of fuels directly into electricity without combustion. They are considered pollution-free because their only byproduct is water vapor, and they are significantly more efficient than thermal plants.

(D) Corrosion $\rightarrow$ (II) Takes place in the presence of air, moisture and $H^+$: Corrosion (e.g., the rusting of iron) is an electrochemical phenomenon. It requires the presence of an oxidizing agent (oxygen in the air) and an electrolyte (moisture). The presence of $H^+$ ions (often from dissolved $CO_2$ forming carbonic acid) acts as a catalyst to accelerate the anodic oxidation of the metal.