Give reasons for the following:
(i) Silver and copper lose their shine when they are exposed to air. Name the substance
formed on their surface in each case.
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(ii) Tarnished copper vessels are cleaned with tamarind juice.
(iii) Aluminium is more reactive than iron yet there is less corrosion of aluminium as
compared to iron when both are exposed to air
Answers
Answer:
A) Silver and copper undergoes corrosion which results in formation of silver. sulphide as silver reacts with atmospheric hydrogen sulphide and copper forms basic copper carbonate when reacts with atmospheric gases.
B) The citric acid present in the lemon or tamarind neutralises the basis copper carbonate and dissolves the layer. That is why, tarnished copper vessels are cleaned with lemon or tamarind juice to give the surface of the copper vessel its characteristic lustre.
C) Aluminium is more reactive than iron yet there is less corrosion of aluminium when both are exposed to air. Aluminium developes a protective(something that protects)layer of aluminium by slowly reacting(to act upon each other)with oxygen present in air.
Answer:
reson air and lemon have Citrix acid so after shine