Why does a copper vessel turn green in open air?
WBBSE
Class X
Physical Science
Metallurgy
02 Mark
2026
Copper reacts slowly with moist air containing oxygen, carbon dioxide and water vapour and forms a green coating of basic copper carbonate [CuCO₃·Cu(OH)₂] on its surface.
Therefore, a copper vessel turns green when exposed to open air for a long time.
Related Questions
More WBBSE Moderate level questions
1/12
Q.
Why is dehydrated calcium chloride added during the extraction of sodium through electrolysis of sodium...
A.
Dehydrated calcium chloride (CaCl2) is added during the electrolysis of sodium chloride...
Q.
In the extraction of metal by the process of electrolysis at which electrode does the...
A.
The reaction occurs at the cathode during the process of electrolysis. This...
Q.
In the extraction of aluminium by the process of electrolysis, the fused mixture used contains...
A.
d. pure alumina. Explanation: In the extraction of aluminium through electrolysis, the...
Q.
Write two reasons why curd and sour fruits are not kept in copper and brass...
A.
Curd and sour fruits contain acids. Therefore, they should not be kept...
Q.
Which of the following elements is not present in Duralumin? (a) Al (b) Zn (c)...
A.
(b) Zn Explanation Duralumin is an alloy composed mainly of: Aluminium (Al)...
Q.
In the extraction of aluminium by electrolysis, what substances are present in the molten mixture...
A.
Besides pure alumina (Al₂O₃), the molten mixture contains: Cryolite (Na₃AlF₆) Fluorspar (CaF₂)...
Q.
Untitled
A.
2.11.1 – (c) 2.11.2 – (d) 2.11.3 – (b) 2.11.4 – (a)
Q.
Match the right column with the left column: 2.11.1. Noble Gas (a) Cs2.11.2. Inver (b)...
A.
Left Column Right Column (1) Noble Gas (b) Rn (2) Inver (d)...
Q.
The metal which is extracted through thermal reduction is
A.
(c) Fe Explanation Iron (Fe) is extracted by thermal reduction (reduction of...
Q.
2.11.1. An alkaline earth metal (a) Fe 2.11.2. The metal which is present in the...
A.
2.11.1 → (c) Ca 2.11.2 → (a) Fe 2.11.3 → (d) K...
Q.
Which of the following is the formula of zine blende, an ore of zinc?
A.
b. ZnS Explanation: Zinc blende is the chief ore of zinc, and...
Q.
What reaction occurs at the cathode in the electrolyte method of extraction of aluminium?
A.
At the cathode in the electrolyte method of aluminium extraction, aluminium ions...