Question

The following table classifies substances into combustible and non-combustible substances.
$$\begin{array}{cc}\text{Combustible}& \text{Non-combustible}\\ \text{Coal}& \text{Glass}\\ \text{Paper}& \text{Cow dung cake}\\ \text{Hydrogen}& \text{Chalk}\end{array}$$ Which of the above entries is not listed correctly?

• A. Chalk
• B. Hydrogen
• C. Glass
• D. Cow dung cake

Answer 1

The correct option is D Cow dung cake

$\bullet$ Combustion is a chemical process in which a substance reacts with oxygen to generate heat.
$\bullet$ The substances that undergo combustion are called combustible substances and those that do not undergo combustion are called non-combustible substances.
$\bullet$ Since, cow dung cake undergoes combustion, it is a combustible substance. Hence, it is listed incorrectly in the table.