CBSE Class 11 Chemistry Redox Reactions Assignment Set B

Question. The oxidation number of phosphorus vary from

(1) – 3 to + 5

(2) – 1 to + 1

(3) – 3 to + 3

(4) – 5 to + 1

Answer (1)

Question. White P reacts with caustic soda, the products are PH3 and NaH₂ PO ₂. The reaction is an example of

(1) Oxidation

(2) Reduction

(3) Disproportionation

(4) Neutralization

Answer (3)

Question. Oxidation number of oxygen atom in O₃ molecule is

(1) 0

(2) –2

(3) + 2

(4) – ½

Answer (1)

Question. Oxidation number of iodine varies from

(1) – 1 to + 1

(2) – 1 to + 7

(3) + 3 to + 5

(4) – 1 to + 5

Answer (2)

Question.The process in which oxidation number increases is

(1) Reduction

(2) Hydrolysis

(3) Oxidation

(4) Decomposition

Answer (3)

Question. The oxidation number of C in CH₄, CH₃Cl, CH₂Cl₂, CHCl₃and CCl ₄ is respectively

(1) –4, –2, 0, +2, +4

(2) +2, 4, 0, –2, –4

(3) 4, 2, 0, –2, 4

(4) 0, 2, –2, 4, 4

Answer (1)

Question. Chlorine is in +3 oxidation number in

(1) HCl

(2) HClO ₄

(3) ICl

(4) ClF₃

Answer (4)

Question. Given that the oxidation number of sulphur is –2, the equivalent weight of sulphur is

(1) 16

(2) 32

(3) 9

(4) 4

Answer (1)

Question.The brown ring complex compound is formulated as [Fe(H₂O)₅ NO]SO₄ . The oxidation state of iron is

(1) +1

(2) + 2

(3) + 3

(4) + 6

Answer (1)

Question.When iron is added to CuSO₄ solution, copper is precipitated. It is due to

(1) Oxidation of Cu⁺²

(2) Reduction of Cu⁺²

(3) Hydrolysis of CuSO₄

(4) Ionization of CuSO₄

Answer (2)

Question. Which one of the following is the correct match?

(1) Cl_2- only reducing agent

(2) HNO₂- only oxidising agent

(3) HNO₃- both oxidising and reducing agent

(4) SO₂- both oxidising and reducing agent

Answer (4)

Question. Oxidation number of sodium in sodium 3 amalgam is

(1) +1

(2) 0

(3) –1

(4) +2

Answer (2)

Question. In a reaction between zinc and iodine, zinc iodide is formed. Which is being oxidised?

(1) Zinc ions

(2) Iodide ions

(3) Zinc atom

(4) Iodine

Answer (3)

Question.Oxidation number of Cr in CrO ₅ is

(1) + 10

(2) + 6

(3) + 4

(4) + 5

Answer (2)

Question.In which of the following compounds, the oxidation number of iodine is fractional?

(1) IF₇

(2) I₃^–

(3) IF₅

(4) IF₃

Answer (2)

Question. Which of the following compound cannot be oxidised by O₃ ?

(1) KI

(2) KMnO₄

(3) K₂MnO₄

(4) FeSO₄

Answer (2)

Question.The oxidation number of sulphur in H₂S₂O₈ is

(1) + 7

(2) + 6

(3) – 6

(4) + 4

Answer (2)

ONE MARK QUESTIONS

1. What do you mean by oxidation number ?

2. Name a compound each in which hydrogen exists in i) +1 ii) -1 oxidation states

3. Define Redox couple.

4. Find the oxidation number of the element underlined 

a) Na₃VO₄     b) K₂CrO₄    c) CH₄    d) SO₂Cl₂   e) NO₂  f) BrF₃  g) Na₂S₄O₆  h) CH₂Cl₂  i) ClO₄-

TWO MARKS QUESTIONS

1. Name a compound each in which oxygen exists in i) +1 ii) -1 iii) +2 iv) -2 oxidation states

2. Define

i) stock notation

i) Standard electrode potential

3. Explain the following by giving example

i) Displacement redox reaction.

ii) Disproportionation reactions

4. Calculate the standard emf of the following cell at 298K using the standard electrode potential.

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