Question

Which of the following substances is smokeless?
A. Charcoal
B. Biogas and LPG
C. Coke
D. All of these

Answer 1

Smokeless is that substance which burns as a non smoke.

Complete step by step solution:
Charcoal is made up of wood. It’s a man made product. We make charcoal by heating the wood at high temperatures in the absence of oxygen. After burning at high temperature the results come out that the wood partially combusts, removing water and impurities and it leaves behind the most pure cotton.
A biogas is a type of the bio-fuel naturally produced from the decomposition of the organic matter. It's renewable and a clean source of energy.
A Liquefied Petroleum Gas, In LPG there is a several mixture of the gases. Gases like, Propane, Butane etc. It consists of the carbon and the hydrogen atoms.
A coke is the excess of the coal left after the harmful distillation and used as the fuel, a similar excess to left by other materials is distilled to dryness. The coke is the excess of the Carbon, with minor amounts of the hydrogen, nitrogen, Sulfur as well as oxygen.
Fuels that burn without smoke are also termed as smokeless fuels.
Smokeless fuels include charcoal, Biogas and LPG, coke etc.

So, the correct answer is “Option D”.

Note: A fuel is a material that can be made to react with other substances, so that it releases the energy as the heath energy or it is used for work. The heat energy is released by the reactions of the fuel.
The fuel is converted into mechanical energy through a heat engine.