JEE Questions for Chemistry Redox Reactions Quiz 2 - MCQExams.com

The loss of electron is termed as
  • oxidation
  • reduction
  • combustion
  • neutralization
The difference in the oxidation numbers of the two types of sulphur atoms in Na2 S4O6 is
  • 4
  • 5
  • 6
  • 7
In the reaction, H2S + H2O2 → S + 2H2 0
  • H2S is an acid and H2O2 is a base
  • H2S is a base and H2O2 is an acid
  • H2S is an oxidising agent and H2O2 is a reducing agent
  • H2S is a reducing agent and H2O2 is an oxidising agent
  • H2S is hydrolysed to S
The oxidation state of Fe in Fe3O4 is
  • +3
  • 8/3
  • +6
  • +2
State the oxidation number of carbonyl carbon in methanal and methanoic acid, respectively
  • 0 and 0
  • 0 and + 2
  • + 1 and + 2
  • + 1 and + 3
For the reaction, NH3 +OCl - → N2 H4 + Cl - occurring in basic medium, the coefficient of N2 H4 in the balanced equation will be
  • 1
  • 2
  • 3
  • 4
In the reaction, SO2 + 2H2S → 3S + 2H2O, the substance oxidised is
  • H2S
  • SO2
  • S
  • H2O

Chemistry-Redox Reactions-6686.png
  • 5
  • 3
  • 4
  • 2
  • 1
Which quantities are conserved in all redox reactions?
  • Charge only
  • Mass only
  • Both charge and mass
  • Neither charge nor mass
The oxidation number of oxygen in KO3 , Na2O2 is
  • 3, 2
  • 1, 0
  • 0, 1
  • - 0.33, -1

Chemistry-Redox Reactions-6689.png
  • 2
  • 3
  • 6
  • 7
When sulphur dioxide is passed in an acidified K2 Cr2 O7 solution, the oxidation state of sulphur is changed from
  • + 4 to 0
  • + 4 to + 2
  • +4 to +6
  • +6 to +4
Among NH3 , HNO3 , NaN3 and Mg3 N2; the number of molecules having nitrogen in negative oxidation state is
  • 1
  • 2
  • 3
  • 4

Chemistry-Redox Reactions-6692.png
  • +6 to +4
  • +6 to +3
  • +8 to +4
  • +4 to +3
The reaction, P4 + 3NaOH + 3H2O → 3NaH2 PO2 + PH3 is an example of
  • disproportionation reaction
  • neutralisation reaction
  • double-decomposition reaction
  • pyrolytic reaction

Chemistry-Redox Reactions-6693.png
  • +10
  • +6
  • +3
  • +2
The oxidation state of sulphur in sodium tetrathionate (Na2S4O6 )is
  • 2
  • 0
  • 2.5
  • 3.5
The number of moles of KMnO4 reduced by one mole of KI in alkaline medium is
  • 1
  • 5
  • 1/2
  • 1/5

Chemistry-Redox Reactions-6695.png
  • zero to + 5
  • + 1 to + 5
  • zero to - 3
  • + 2 to + 5
Oxidation states of X, Y, Z are + 2, + 5 and - 2 respectively. Formula of the compound formed by these will be
  • X2YZ6
  • XY2Z6
  • XY5
  • X3YZ4
In standardization of Na2S2O3 using K2Cr2O7 by iodometry, the equivalent weight of K2Cr2O7 is
  • (molecular weight)/6
  • (molecular weight)/2
  • (molecular weight)/3
  • Same as molecular weight
Which is the best description of behaviour of bromine in the reaction given below ?
H2O + Br2 → HBr + HOBr
  • Proton acceptor only
  • Both oxidised and reduced
  • Oxidised only
  • Reduced only

Chemistry-Redox Reactions-6696.png
  • 6
  • 2
  • 4
  • 3
Oxidation number of sulphur in Caro's acid is
  • +6
  • +4
  • +8
  • +7
Oxidation state of sulphur in Na2 S2 O3 and Na2 S4 O6
  • 4 and 6
  • 3 and 5
  • 2 and 2.5
  • 6 and 6
One mole of acidified K2 Cr2 O7 on reaction with excess KI will liberate......... mole(s) of I2.
  • 6
  • 1
  • 7
  • 2
  • 3
Which of the following reaction involves oxidation and reduction ?
  • NaBr + HCl → NaCl + HBr
  • HBr + AgNO3 → AgBr + HNO3
  • H2 + Br2 → 2HBr
  • Na2O + H2SO4 → Na2SO4 + H2O
The oxidation states of iodine in HIO4, H3IO5 and H5IO6 respectively, are
  • +1, +3, +7
  • + 7, +7, +3
  • + 7, +7, +7
  • + 7, +5, +3
Which of the following acts as an oxidising as well as reducing agent ?
  • Na2O
  • Na2O2
  • NaNO3
  • NaNO2
In which of the following reactions, H2O2 acts as a reducing agent?
H2O2 + 2H+ + 2e- → 2H2O
H2O2 - 2e- → O2 + 2H+
H2O2 - 2e- → O2 + 2H-
H2O2 + 2H+ + 2e- → O2 + 2H2O
  • I and II
  • III and IV
  • I and III
  • II and III
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