Question

Coal tar which is the main source of organic compounds is obtained as a by-product during?
(A)- destructive distillation of wood
(B)- destructive distillation of bones
(C)- destructive distillation of coal
(D)- all of these

Answer 1

Hint: The process in which the organic substance is treated in an inert atmosphere, wherein the volatile substances are distilled out. Various by-products are formed, depending on the initial substance used as given, we can determine the coal tar as the by-product.

Complete step by step answer:
-The destructive distillation is a chemical process in which the unprocessed organic substance is decomposed by subjecting it to heating at higher temperatures, in the absence of oxygen. So, the large substance is broken down into simpler substances and by-products.
-In the destructive distillation of coal, the volatile material is distilled out and the solid residue is left behind in the apparatus. The main distilled product formed is the coal gas, which is used in fuel as the source of energy. Along with other volatile by-products as coal tar and ammonia and the solid residue of coke. All these products formed are commercially valuable.
-The coal tar as the by-product has various industrial and medicinal applications. Such as in shampoos and soaps for it kills the head lice and treats the dandruff and psoriasis due to its anti-inflammatory and anti-fungal properties.
-In industries, it is used in manufacturing of pesticides, insecticides, paints, dyes, and perfumes. It is also used to make the Naphthalene balls which are moth-repellents.

Therefore, Coal tar which is the main source of organic compounds is obtained as a by-product during option (C)- destructive distillation of coal.

Note: Unlike the process of combustion of the organic matter, in which the amount of product produced is nearly the same as the amount of initial matter and the oxidant consumed. In the destructive distillation process, less amount of initial matter is used and also a considerable portion is retained back in the form of ash and char.