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Question
Chemistry
Assertion: Solution of Na2CrO4 in water is coloured. Reason: Oxidation state of Cr in Na2CrO4 is +6.
Q.
Assertion :
Solution of
N
a
2
C
r
O
4
in water is coloured.
Reason :
Oxidation state of
C
r
in
N
a
2
C
r
O
4
is
+
6
.
2497
188
AIIMS
AIIMS 2003
The d-and f-Block Elements
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A
If both assertion and reason are true and the reason is the correct explanation of the assertion
60%
B
If both assertion and reason are true and the reason is not the correct explanation of the assertion
0%
C
If assertion is true but reason is false
40%
D
If both assertion and reason are false
0%
Solution:
N
a
2
C
r
O
4
solution in water is yellow in colour,
when acidified changes to orange colour (due to the formation of
C
r
2
O
2
2
−
ions).
N
a
2
C
r
O
4
+
H
2
S
O
4
⟶
N
a
2
C
r
2
O
7
+
N
a
2
S
O
4
+
H
2
O
Oxidation state :
N
a
2
C
r
O
4
Let oxidation state of
C
r
be
x
.
⇒
2
(
+
1
)
+
x
+
4
(
−
2
)
=
0
⇒
x
=
+
6
.