The alloy used for welding and plumbing contains

Analyze the question: We need the alloy used for welding and plumbing, which is solder.

Concept: Solder is an alloy of lead and tin. It has a low melting point (roughly 180-250 °C depending on the ratio), so it melts easily and joins metal pieces or pipes together when it cools and solidifies. Plumbers use it to seal joints in pipes, and it is also used in electrical work.

Checking each option:

• A. Aluminum and copper: this is not solder. Alloys of these metals (e.g., duralumin-type alloys) are used in aircraft parts.
• B. Copper and tin: this is bronze, used for statues, medals, and bells.
• C. Iron and aluminum: this is not a common alloy used for joining.
• D. Lead and antimony: this is type metal, used in printing, and also in battery plates.
• E. Lead and tin: this is solder, used for welding (joining) and plumbing.

Answer: E, lead and tin.

Tip: Link the words to the alloys:

• Solder = lead + tin (joins things)
• Bronze = copper + tin
• Brass = copper + zinc
• Type metal = lead + antimony (printing)