The residue of coal decomposition that is used in the manufacture of steel is called: 1. coal gas 2. coke 3. coal tar

The residue of coal decomposition in the manufacture of steel is coal tar. It is a by product of the coking process in the blast furnace. Coal gas is another by product but is not the answer becuase this is not a residue which is a solid. Coal gas is a gas. Coke in fact is one of the reactants fed for steel making. Answer is choice 3.