Question
Answers

Thermite mixture used for welding is:
A.$Fe$ and $Al$
B.Ferric oxide and aluminium powder
C.$Cu$ and $Al$
D.Barium peroxide and aluminium oxide

Answer Verified Verified
Hint: At first think about the welding process and the components involved in it. Thermite welding is a chemical welding process where the exothermic reaction is used to provide the needed heat energy.

Complete step by step answer:
Thermite welding is a process where heat generated from an exothermic chemical reaction is used for fusion. The chemical reaction aluminothermic process occurs between metal oxide and aluminium powder. Thermite used for welding is ferric oxide and aluminium powder.
So the answer is B.
Additional Information:-Thermite welding is a welding process that employs molten metal to permanently join the conductors. The process employs an exothermic reaction of a thermite composition to heat the metal and requires no external source of heat or current. This reaction generates a molten metal that acts as filler metal joining the work pieces on solidification. This process is mainly used for the joining steel pieces. In this welding, aluminium dust reduces the oxide of another metal, most commonly iron oxide because aluminium is highly reactive.
$F{e_2}{O_3} + 2Al \to 2Fe + A{l_2}{O_3}$
When a thermite process is used for track circuits , the bonding of wires to the rails with a copper alloy, a graphite mould is used. The graphite mould is reusable many times, because the copper alloy is not as hot as the steel alloys used in rail welding. Copper thermite, using copper oxide, is used for creating electric joints.
Note: Thermite welding is widely used to weld railway rails. The weld quality of chemically pure thermite is low due to the low heat penetration into the joining metals and the very low carbon and alloy content in the nearly pure molten iron.