Assertion : Aqueous gold colloidal sol is red in colour.
Reason : The colour arised due to scattering of light by particles of gold.

Options

A. If both (A) and (R) are correct, and (R) is the correct explanation of (A)
B. If both (A) and (R) are correct, but (R) is the correct explanation of (A).
C. If (A) is correct, but (R) is incorrect.
D. If (A) is incorrect, but (R) is correct. S

Answer

A

Explanation

The colours is due to scattering. It depends upon the size of particles. Finest gold sol has red colour. As the size of the particles increases, it becomes purple, then blue, and finally golden yellow.