Assertion : Desilverisation of lead is done by Parke's method `DeltaG`.
Reason : When lead-silver alloy is poor in silver, zinc is added to molten ore.

Assertion : Desilverisation of lead is done by Parke's method. Reason : When lead-silver alloy is poor in silver, zinc is added to molten ore.

Assertion : Gold and silver are extracted from their native ores by leaching. Reason : Both silver and gold particles dissolve in dilute solution of sodium cyanide in presence of oxygen.

Assertion : Gold and silver are extracted from their native ores by leaching. Reason : Both silver and gold particles dissolve in dilute solution of sodium cyanide in presence of oxygen.

Assertion , Silver ores and native gold have to be leached with metal cyanides. Reason : Silver and gold do not form complex ion with cyanide ion.

Assertion : Lead, tin and bismuth are purified by liquation method. Reason : Lead, tin and bismuth have low m.p. as compared to impurities.

Assertion : Lead, tin and bismuth are purified by liquation method. Reason : Lead, tin and bismuth have low m.p. as compared to impurities.