Question

A light lustrous substance used in metallurgical furnaces or any other industrial furnaces is known as _______.

• A. hard coke
• B. coal
• C. tar
• D. lampblack

Answer 1

The correct option is A hard coke

Coke is a grey, hard, and porous fuel with a high carbon content and few impurities, made by heating coal or oil in the absence of air—a destructive distillation process.
Coal is a brownish black rock formed when dead plant matter decays over millions of years. It is used as fuel.
Tar is a black liquid of hydrocarbon obtained through destructive distillation.
Lampblack is a finely powdered black coloured soot deposited during the incomplete combustion of carbonaceous materials.