Two metals zinc and tin are dissolved separately in definite proportions in molten copper (the primary metal) to obtain two different alloys respectively known as:

As per Section 3.5.1 of the NCERT chapter, an alloy is a homogeneous mixture of two or more metals (or a metal and non-metal), prepared by melting the primary metal and dissolving the other element(s) in it in definite proportions, then cooling. The text explicitly states: 'brass, an alloy of copper and zinc (Cu and Zn), and bronze, an alloy of copper and tin (Cu and Sn)'. Here copper is the primary (base) metal in both cases.

• Dissolving zinc in molten copper gives brass.
• Dissolving tin in molten copper gives bronze.

So the correct pairing is Brass and Bronze respectively — option (C).

• (A) Bronze and Brass — Incorrect: this reverses the order; zinc-in-copper gives brass (not bronze), and tin-in-copper gives bronze (not brass).
• (B) Brass and Solder — Incorrect: the second alloy should be with tin in copper, which is bronze, not solder. Solder (Pb + Sn) does not involve copper as the primary metal at all — it is used for welding electrical wires, as stated in the chapter.
• (D) Solder and Bronze — Incorrect: zinc dissolved in copper is brass, not solder; solder has no copper in it.