Question

what are the
combustible substance

Answer 1

Substance can be classified into types on the basis of certain properties they possess. On the basis of combustion i.e. if it burns easily or not, substances are classified into two types, namely:

$\star$Combustible Substances

$\star$Non-combustible substances

From their names it is very clear that the first group(Combustible Substances) includes the substances which burns easily or in order words, the substances which catches fire very easily. To name some of the substances which fall under this group are petrol and diesel.

Also it is very clear from the names that the second group is just opposite of the combustible substances. This group includes the substances which hardly burns or which catches fire very rarely. Some substances falling under this group of classification are iron, bricks etc.

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