(a) Gold
(b) Copper
(c) Zinc
(d) Mercury
Solution|||
(a) no displacement reaction will take place with the solution of copper sulphate, as gold is less reactive then the copper.
(b) there will not be any reaction between copper and copper sulphate.
(c) copper will be replaced by zinc from the copper sulphate
(d) in case of mercury no displacement reaction will take place as mercury is less reactive then copper.