German Silver is an alloy that is primarily composed of copper, zinc, and nickel. It is commonly used in the production of various items, including coins, musical instruments, and jewelry. Nickel is a key component of German Silver, giving it its distinctive silver-like appearance.

Solder is a material used for joining or bonding metal surfaces together. It is typically made of a combination of tin and lead or other metals. Tin is the primary component of solder, providing its ability to create strong and durable connections between metal parts.

Bleaching Powder, also known as calcium hypochlorite, is a chemical compound used for various purposes, including disinfection, water treatment, and bleaching. It is produced by reacting chlorine gas with calcium hydroxide. Chlorine is a crucial component in the production of bleaching powder, providing its powerful bleaching and disinfecting properties.

Hypo, also known as sodium thiosulfate, is a chemical compound commonly used in photography as a fixing agent. It is used to remove or fix unexposed silver halide from photographic films and prints. Sodium is an essential component of hypo, providing its fixing properties in photographic processes.

Therefore, the correct matching between List I and List II is as follows:

I. German Silver - (B) Nickel

II. Solder - (A) Tin

III. Bleaching Powder - (D) Chlorine

IV. Hypo - (C) Sodium

Therefore, the correct answer is:

I-B, II-A, III-D, IV-C