If Cl2 is passed through hot aqueous NaOH, the products formed have Cl in different oxidation states. These are indicated as
-1 and +1
-1 and +5
+1 and +5
-1 and +3
When a manganous salt is fused with a mixture of KNO3 and solid NaOH, the oxidation number of Mn changes from +2 to
+4
+3
+6
+7
The reaction that takes place when Cl2 gas is passed through conc. NaOH solution is
oxidation
reduction
displacement
disproportionation
The brown complex obtained in the detection of nitrate radical is formulated as [Fe(H2O)5NO]SO4. What is the oxidation number of Fe in this complex?
+1
+2
+3
0
Excess of KI reacts with CuSO4 solution and then Na2S2O3 solution is added to it. Which of the statements is incorrect for this reaction ?
Cu2I2 is formed
CuI2 is formed
Na2S2O3 is oxidised
Evolved I2 is reduced
B.
CuI2 is formed
Copper sulphate reacts with KI to give cuprous iodide and iodine.
2CuSO4 + 4KI ➔ Cu2I2 + 2K2SO4 + I2
I2+ 2Na2S2O3 ➔ Na2S4O6 + 2Nal
In the second reaction oxidation number of I2 changes from zero (in I2) to -1 (in NaI). Thus, it is reduced. Oxidation number of S changes from +2 (in Na3S2O5) to 2.5 (in Na2S2O6). Thus, Na2S2O3 is oxidised.
Which of the following reaction involves oxidation and reduction?
NaBr + HCl → NaCl + HBr
HBr + AgNO3 → AgBr + HNO3
H2 + Br2 → 2HBr
Na2O + H2SO4 → Na2SO4 + H2O
Which of the following reactions are disproportionation reaction?
(a) 2Cu+ → Cu2+ + Cu0
(b) 3MnO
(c) 2KMnO4
(d) 2MnO
Select the correct option from the following
(a), (b) and (c)
(a), (c) and (d)
(a) and (d) only
(a) and (b) only