Question

You must have seen tarnished cooper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels.

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Answer 1

Explanation:

Copper reacts with moist carbon dioxide in air to form copper carbonate and as a result, copper vessel loses its shiny brown surface forming a green layer of copper carbonate. 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.

Answer 2

The reason for this question is explained below.

Explanation:

• It is fundamental chemistry that the acids and bases neutralise each other to form a salt.
• When any copper vessel or utensil is left in the air uncovered, it gets coated with metal oxide by reacting with oxygen.
• Any metal oxide will be basic in nature and any non-metal oxide will be acidic in nature. Here we have copper oxide (MO) which is a base and will be neutralised by an acid.
• So, that's why we can remove the tarnished copper layer by using an acid like lemon or tamarind juice.