Question

Why is solder used for welding electrical wires?
A.Because the constituent alloys are cheap
B.Because it has less melting point
C.Because it has high melting point
D.Because it is very light

Answer 1

Solder is an alloy of both lead and tin (Pb and Sn). Lead and tin both are metal and have low melting points. Here, we will use the concept that for welding electrical wires low melting point elements are used.

Complete answer:
We know, solder is an alloy of lead and tin (Pb and Sn).
Lead is a chemical element with the symbol Pb and atomic number 82. Lead is soft and malleable; it has a low melting point of 327.5 °C.
Tin is a chemical element with the symbol Sn and has atomic number 50. It is a silvery metal and has a low melting point of 231.97°C.
It contains 50% of lead and 50% of tin.
The melting point of a substance depends on pressure and is usually specified at a standard pressure like- 1atm or one atmospheric temperature.
Solder is an alloy which has a low melting point.

Therefore, option B) is correct i.e., solder is used for welding electrical wires because it has less melting point.

Additional information:
Lead and tin both are metals. Metals are good conductors of heat and the electricity, malleable i.e., they can be drawn into sheets, ductile i.e., they can be drawn into wire. Most of the metals are solid at room temperature, generally having silvery shine character.
In the periodic table, metals are found in the center and left side whereas nonmetals are in the right side.
Periodic table also has metalloids, which behave as both metals and nonmetals and are present on both sides.

Note:
It can be seen that both lead and tin have low melting point, and a solder is made of both, therefore it can be directly answered that due to low melting point solder is used to weld the electrical wire.