question_answer

Pick out the statement which is not relevant in the discussion of colloids                    

A) Sodium aluminium silicate is used in the softening of hard water

B) Potash alum is used in shaving rounds and as antiseptic in medicine

C) Artificial rain is caused by throwing electrified sand on the clouds from an aeroplane 

D) Deltas are formed at a place where the river pours its water into the sea