JEE Chemistry Redox Reactions MCQs Set A

Question: Which of the following process takes place in oxidation process?

• a) Addition of oxygen
• b) Removal of oxygen
• c) Addition of hydrogen
• d) Addition of chlorine

Answer: Addition of oxygen

Question:

• a) removal of electropositive element potassium from potassium ferrocyanide (K₄[Fe(CN)₆])
• b) All of the above are the correct reasons
• c) addition of electropositive potassium to H₂O₂
• d) removal of a hydrogen from H₂O₂

Answer: removal of electropositive element potassium from potassium ferrocyanide (K₄[Fe(CN)₆])

Question: In the reaction given below, identify the species undergoing redox reaction

• a) Both
• b) Na is oxidised and hydrogen is reduced
• c) Na undergoes oxidation and hydrogen undergoes reduction
• d) None of these

Answer: Both

Question: The loss of electron is termed as

• a) oxidation
• b) combustion
• c) neutralization
• d) reduction

Answer: oxidation

Question: Which of the following is correct code for x and y in the following reaction

• a) (i) and (iv)
• b) (iii) and (iv)
• c) (i) and (ii)
• d) (ii) and (iii)

Answer: (i) and (iv)

Question: Which of the following involves transfer of five electrons ?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Which reaction involves neither oxidation nor reduction?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) phosphorus is both oxidised and reduced
• b) only phosphorus is reduced.
• c) phosphorus is not oxidised
• d) None of these

Answer: phosphorus is both oxidised and reduced

Question: Which one of the following reaction involves oxidationreduction ?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) reducing agent
• b) None of these
• c) oxidising agent
• d) Both

Answer: reducing agent

Question:

• a) redox reaction
• b) oxidation
• c) reduction
• d) None of the above

Answer: redox reaction

Question: One mole of N₂H₄ loses 10 moles of electrons to form a new compound, y. Assuming that all nitrogen appear in the new compound, what is the oxidation state of nitrogen in y (There is no change in the oxidation state of hydrogen )

• a) +3
• b) –1
• c) –3
• d) +5

Answer: +3

Question: When a strip of metallic zinc is placed in an aqueous solution of copper nitrate the blue colour of the solution disappear due to formation of

• a) Zn²⁺
• b) Cus
• c) Cu²⁺
• d) ZnS

Answer: Zn²⁺

Question: The correct order of electron releasing tendency of the metals Cu, Zn and Ag is in the order

• a) Zn > Cu > Ag
• b) Zn > Ag > Cu
• c) Cu > Zn > Ag
• d) Ag > Zn > Cu

Answer: Zn > Cu > Ag

Question: What is the oxidation number of elements in the free or in the uncombined state ?

• a) 0
• b) –1
• c) +1
• d) +2

Answer: 0

Question: In which of the following compounds oxygen has highest oxidation state and in which it has lowest oxidation state?

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question: ‘Oxidation number of H in NaH, CaH₂ and LiH, respectively is

• a) –1,–1, –1
• b) –1, +1, + 1
• c) +1, +1, –1
• d) +1, + 1, + 1

Answer: –1,–1, –1

Question: Which of the following is the correct representative of stock notation for auric chloride?

• a) Au(III)Cl₃
• b) Au(II)Cl₂
• c) Au(I)Cl₂
• d) None of these

Answer: Au(III)Cl₃

Question: Oxidation number of N in HNO₃ is

• a) + 5
• b) + 3.5
• c) – 3.5
• d) –5

Answer:  + 5

More Questions...............................

Question: In which of the following reactions, there is no change in valency ?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: The oxidation number of chromium in potassium dichromate is

• a) + 6
• b) – 2
• c) – 5
• d) + 2

Answer: + 6

Question: The oxidation number of sulphur in S₈, S₂F₂, H₂S respectively, are

• a) 0, +1 and –2
• b) 0, +1 and +2
• c) +2, +1 and –2
• d) –2, +1 and –2

Answer: 0, +1 and –2

Question: Oxidation number of cobalt in K[Co(CO)₄] is

• a) –1
• b) –3
• c) +3
• d) +1

Answer:  –1

Question: Oxidation number of nitrogen in (NH₄)₂SO₄ is

• a) –3
• b) –1
• c) –1/3
• d) +1

Answer: –3

Question: Oxidation number of carbon in CH₂Cl₂ is

• a) 0
• b) –4
• c) +4
• d) –2

Answer: 0

Question: In which of the following compounds, iron has lowest oxidation state?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: The oxidation state of osmium (Os) in OsO₄ is

• a) +8
• b) +6
• c) +7
• d) +4

Answer: +8

Question:  Which of the following transition metal has zero oxidation state ?

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question: In which of the compounds does 'manganese' exhibit highest oxidation number ?

• a) NOClO₄
• b) NH₂.NH₂
• c) CrO₅
• d) None of these

Answer: NOClO₄

Question: In which of the compounds does 'manganese' exhibit highest oxidation number ?

• a) K₂MnO₄
• b) MnSO₄
• c) Mn₃O₄
• d) MnO₂

Answer: K₂MnO₄

Question: Among the following, identify the species with an atom in +6 oxidation state

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question: In which of the following compounds the oxidation number of carbon is not zero?

• a) CH₃CHO
• b) CH₃COOH
• c) HCHO
• d) C₁₂H₂₂O₁₁

Answer: CH₃CHO

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

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:  A metal ion M³⁺ loses 3 electrons, its oxidation number will be

• a) +6
• b) –3
• c) +3
• d) 0

Answer: +6

Question: The correct name for NO₂ using stock notation is

• a) nitrogen (iv) oxide
• b) All of these
• c) nitrogen dioxide
• d) nitrogen per oxide

Answer: nitrogen (iv) oxide

Question: The oxide, which cannot act as a reducing agent, is

• a) CO₂
• b) NO₂
• c) SO₂
• d) ClO₂

Answer: CO₂

Question: The oxidation state of Fe in Fe₃O₄ is

• a) 8/3
• b) + 2
• c) + 3
• d) + 6

Answer: 8/3

Question: In oxygen difluoride, the oxidation number of oxygen is

• a) + 2
• b) – 2
• c) – 1
• d) +1, – 2

Answer: + 2

Question: Oxygen has an oxidation state of +2 in the compound

• a) F₂O
• b) CO₂
• c) H₂O₂
• d) H₂O

Answer: F₂O

Question:  The number of electrons involved in the reduction of one nitrate ion to hydrazine is

• a) 7
• b) 5
• c) 8
• d) 3

Answer: 7

Question: The standard reduction potentials at 298K for the following half reactions are given against each

• a) Zn (s)
• b) H₂(g)
• c) Cr (s)
• d) Fe³⁺(aq)

Answer: Zn (s)

Question:

• a) Li
• b) H₂
• c) Zn
• d) Ag

Answer: Li

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) Cu will reduce Br₂
• b) Cu will reduce Ag
• c) Cu will reduce Br ^–
• d) Cu will reduce I ^–

Answer: Cu will reduce Br₂

Question: Arrange the following in the order of their decreasing electrode potentials : Mg, K, Ba and Ca

• a) Ca, Mg, K, Ba
• b) K, Ca, Ba, Mg
• c) Ba, Ca, K, Mg
• d) Mg, Ca, Ba, K

Answer: Ca, Mg, K, Ba

Question: The standard electrode potentials of four elements A, B, C and D are –3.05, –1.66, –0.40 and +0.80. The highest chemical reactivity will be exhibited by

• a) A
• b) C
• c) B
• d) D

Answer: A

Question:

• a) (i), (ii) and (iv)
• b) (iii) and (iv)
• c) (i) and (ii)
• d) (iii) only

Answer: (i), (ii) and (iv)

Question: Which of the following sequences of T and F is correct for given statements. Here T stands for true and F stands for false statements

(i) Reducing agents lower the oxidation number of an element in a given substance. These reagents are also called as reductants
(ii) Reducing agents are acceptor of electrons
(iii) Loss of electron(s) by any species is called oxidation reaction
(iv) Oxidation and reduction always occur simultaneously.

• a) TFTT
• b) FTTT
• c) TTTT
• d) TFFT

Answer: TFTT

Question:  If aqueous solution of H₂O₂ is made acidic. For this which of the following statement(s) is/are correct ?

(i) This aqueous solution oxidizes I^–
(ii) This aqueous solution oxidizes F^–

• a) Statement (i) is correct and (ii) is incorrect
• b) Statement (ii) is correct and (i) is incorrect
• c) Both statements (i) and (ii) are incorrect
• d) Both statements (i) and (ii) are correct

Answer: Statement (i) is correct and (ii) is incorrect

Question:  Which of the following statement(s) is/are correct ?

(i) All alkali metals and some alkaline earth metals (Ca, Sr and Ba) displace hydrogen from cold water.
(ii) Magnesium and iron react with steam as well as acids to produce hydrogen gas.
(iii) Cadmium and tin do not react with steam but displace hydrogen from acids.

• a) (i), (ii) and (iii)
• b) (ii) only
• c) (i) and (ii)
• d) (i) and (iii)

Answer: (i), (ii) and (iii)

Question:

• a) (i), (ii) and (iii)
• b) (i) and (ii)
• c) (ii) and (iii)
• d) (i) only

Answer: (i), (ii) and (iii)

Question:

• a) Only (i)
• b) Both (i) and (ii)
• c) only (ii)
• d) Neither (i) nor (ii)

Answer: Only (i)

Question: Which of the following statement(s) is/are correct ?

(i) Oxidation state of carbon in C₃H₄ is –(4/3).
(ii) Electrons are never shared in fraction.

• a) (i) and (ii)
• b) Only (i)
• c) Neither (i) nor (ii)
• d) Only (ii)

Answer: (i) and (ii)

Question:

• a) (A) – (p), (B) – (p), (C) – (q), (D) – (q)
• b) (A) – (p), (B) – (q), (C) – (q), (D) – (p)
• c) (A) – (p), (B) – (q), (C) – (p), (D) – (q)
• d) (A) – (q), (B) – (q), (C) – (p), (D) – (p)

Answer:  (A) – (p), (B) – (p), (C) – (q), (D) – (q)

Question:

• a) A – (r), B – (s), C – (p), D – (q)
• b) A – (s), B – (r), C – (q), D – (p)
• c) A – (r), B – (p), C – (s), D – (q)
• d) A – (s), B – (q), C – (p), D – (r)

Answer:  A – (r), B – (s), C – (p), D – (q)

Question:

• a) A – (r), B – (p), C – (q), D – (s)
• b) A – (s), B – (r), C – (p), D – (q)
• c) A – (r), B – (s), C – (p), D – (q)
• d) A – (s), B – (q), C – (p), D – (r)

Answer: A – (r), B – (p), C – (q), D – (s)

Question:

• a) A – (s), B – (r), C – (p), D – (q)
• b) A – (s), B – (q), C – (r), D – (p)
• c) A – (r), B – (s), C – (q), D – (p)
• d) A – (r), B – (s), C – (p), D – (q)

Answer: A – (s), B – (r), C – (p), D – (q)

Question:

• a) Assertion is correct, reason is incorrect
• b) Assertion is incorrect, reason is correct
• c) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
• d) Assertion is correct, reason is correct; reason is a correct explanation for assertion

Answer: Assertion is correct, reason is incorrect

Question:

• a) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
• b) Assertion is correct, reason is incorrect
• c) Assertion is incorrect, reason is correct
• d) Assertion is correct, reason is correct; reason is a correct explanation for assertion

Answer: Assertion is correct, reason is correct; reason is not a correct explanation for assertion

Question:

• a) Assertion is correct, reason is correct; reason is a correct explanation for assertion
• b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
• c) Assertion is correct, reason is incorrect
• d) Assertion is incorrect, reason is correct

Answer:  Assertion is correct, reason is correct; reason is a correct explanation for assertion