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The Statue of Liberty is one of the seven wonders. It is present on Liberty island in New York harbour in U.S.A. It is made up of a metal. Over a period of time, the metal's colour has changed and statue gives greenish look.
Answer the following questions based on the above information :
(A) What is corrosion ?
(B) Why do silver articles turn black after some time?
Answer the following questions based on the above information :
(A) What is corrosion ?
(B) Why do silver articles turn black after some time?
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The slow and gradual degradation of metals due to their reaction with moisture, acids etc. present in the atmosphere is called corrosion. (1 Mark)
Silver articles react with sulphur in the air to form a coating of silver sulphide, which is black in colour. (1 Mark)
A – Carbon dioxide/ $\ce{CO2}$ (1 Mark)
Green coating is of copper carbonate/ $\ce{CuCO3}$ (1 Mark)
OR
An alloy is a homogenous mixture of two or more metals, or a metal and a non-metal. (1 Mark)
It is made by mixing the metals in molten state. (1 Mark)
Silver articles react with sulphur in the air to form a coating of silver sulphide, which is black in colour. (1 Mark)
A – Carbon dioxide/ $\ce{CO2}$ (1 Mark)
Green coating is of copper carbonate/ $\ce{CuCO3}$ (1 Mark)
OR
An alloy is a homogenous mixture of two or more metals, or a metal and a non-metal. (1 Mark)
It is made by mixing the metals in molten state. (1 Mark)