Question

Addition of NaCl solution to gold sol results in
its coagulation. But if this reaction is carried out
in the presence of a certain amount of soluble
starch, precipitation of gold does not take place.
Explain.

Answer 1

Answer:

0.25gm of starch needed to prevent coagulation of 10% NaCl to 10ml gold.sol.

Amount of starch =0.25gm=250mg.

So, the gold number of starch is 250.

So, Option-D ⇒ none of these.