When sulphur dioxide is passed in an acidified K2Cr2O7 solution, the oxidation state of sulphur is changed from
+4 to 0
+4 to +2
+ 4 to +6
+6 to +4
For the decomposition of a compound AB at 600 K, the following data were obtained
[AB] mol dm-3 | Rate of decomposition of AB in mol dm-3 |
0.20 | 2.75 × 10-8 |
0.40 | 11.0 × 10-8 |
0.60 | 24.75 × 10-8 |
The order for the decomposition of AB is
1.5
0
1
2
A miscible mixture of C6H6 + CHCl3 can be separated by
sublimation
distillation
filtration
crystallisation
The heat of combustion of carbon to CO2 is -393.5 kJ/ mol. The heat released upon formation of 35.2 gm of CO2 from carbon and oxygen gas is:
+315 kJ
-31.5 kJ
-315 kJ
+31.5 kJ
Which of the following substances acts as an oxidising as well as a reducing agent ?
Na2O
SnCl2
Na2O2
NaNO2
3ClO-(aq) → ClO- + 2Cl is an example of
Oxidation reaction
reduction reaction
disproportionation reaction
decomposition reaction
When K2Cr2O7 is converted into K2CrO4, the change in oxidation number of chromium is :
0
5
7
9
A.
0
Let, oxidation state of Cr in K2Cr2O7 = x
(+1 × 2) + 2x + (-2 × 7) = 0
+2 + 2x - 14 = 0
x = +6
Let oxidation state of Cr in K2CrO4 = x
+1 × 2 + x + (-2 × 4) = 0
2 + x - 8 = 0
x = 6
Therefore, change in oxidation state of Cr is zero when it changes from K2Cr2O7 to K2CrO4.