The disperse phase in colloidal iron (III) hydroxide and colloidal gold is positively and negatively charged, respectively. Which of the following statements is not correct ?

Question

( A ) Sodium sulphate solution causes coagulation in both sols
( B ) Mixing the sol has no effect
( C ) Coagulation in both sols can be brought about by electrophoresis
( D ) Magnesium chloride solution coagulates, the gold sol more readily than the iron (III) hydroxide sol