Question

Describe a comspicuous change observed when
(i) a solution of `NaCl` is added to a sol of hydrated ferric oxide.
(ii) a beam of light is passed through a solution of NaCl and then through a sol.

Answer 1

(i) Addition of `NaCl` is added to a sol of hydrated ferric oxide `(Fe_(2)O_(3))` causes coagualation.
(ii) When a beam of light is passed through a solution of `NaCl`, no tyndall effect is produced.
But when it passed through a sol. tyndal effect is produced.