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Question
Chemistry
Calcium is tarnished in air, because it is covered with a thin film of
Q. Calcium is tarnished in air, because it is covered with a thin film of
1975
156
NTA Abhyas
NTA Abhyas 2020
The s-Block Elements
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A
oxide
75%
B
hydroxide
0%
C
carbonate
19%
D
basic carbonate
6%
Solution:
Calcium is tarnished in air, because it is covered with a thin film of oxide.
C
a
+
O
2
→
2
C
a
O
In moist air, it is slowly tarnished, but decomposes water fairly rapidly giving hydrogen.
C
a
+
2
H
2
O
→
C
a
(
O
H
)
2
+
H
2