Question

Assertion : All halogens are coloured.
Reason : The halogens absorb visible light.

• A. If both assertion and reason are true and reason is a correct explanation of the assertion
• B. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
• C. If the assertion is true but the reason is false
• D. If both the assertion and reason are false

Answer 1

Answer: (A)

All the halogens are coloured. The colour deepens with the rise of atomic number from fluorine to iodine. The colour is due to the absorption of energy from visible light by their molecules or excitation of outer electrons to higher energy levels.

$\begin{array}{cccc}F& Cl& Br& I\\ \text{ Light }& \text{ Yellow }& \text{ Reddish }& \text{ Deep }\\ \text{ yellow }& \text{ green }& \text{ brown }& \text{ violet. }\end{array}$