Questions on Oxidation-Reduction Reactions (Redox Reactions):

Ques. The compound YBa₂Cu₃O₇ which shows superconductivity has copper in oxidation state …….. Assume that the rare earth element Yttrium is in its usual +3 oxidation state
(a) 3/7
(b) 7/3
(c) 3
(d) 7

Ans. (b)

Ques. The oxidation state of I in H₄IO^–6 is
(a) + 7
(b) + 5
(c) + 1
(d) – 1

Ans. (a)

Ques. The oxidation number of hydrogen in LiH is
(a) + 1
(b) – 1
(c) 2
(d) 0

Ans. (b)

Ques. The number of moles of KMnO₄reduced by one mole of KI in alkaline medium is:
(a) One fifth
(b) five
(c) One
(d) Two

Ans. (d)

Related: Amines online MCQ quiz

Ques. A metal ion M³⁺after loss of three electrons in a reaction will have an oxidation number equal to
(a) Zero
(b) + 2
(c) + 3
(d) + 6

Ans. (d)

Ques. Starch paper is used to test for the presence of
(a) Iodine
(b) Oxidising agent
(c) Iodide ion
(d) Reducing agent

Ans. (a)

Ques. Oxidation number of S in Na₂SO₄is
(a) – 2
(b) + 2
(c) – 6
(d) + 6

Ans. (d)

Ques. The oxidation state of I in IPO₄ is
(a) +1
(b) +3
(c) +5
(d) +7

Ans. (b)

Ques. The oxidation state of sulphur in SO₄^2–is
(a) 4
(b) 2
(c) 6
(d) – 6

Ans. (c)

Ques. Oxidation state of ‘S’ in H₂SO₃
(a) + 3
(b) + 6
(c) + 4
(d) + 2

Ans. (c)

Ques. The oxidation state of each oxygen atom in Na₂O₂ is
(a) – 2 each
(b) – 2 and zero
(c) – 1 each
(d) None of these

Ans. (c)

Ques. The most common oxidation state of an element is –2. The number of electrons present in its outermost shell is
(a) 4
(b) 2
(c) 6
(d) 8

Ans. (c)

Related: Chemical bonding questions

Ques. In the reaction between ozone and hydrogen peroxide, H₂O₂ acts as
(a) Oxidising agent
(b) Reducing agent
(c) Bleaching agent
(d) Both oxidising and bleaching agent

Ans. (b)

Ques. For decolourization of 1 mole of KMnO₄, the moles of H₂O₂ required is
(a) 1/2
(b) 3/2
(c) 5/2
(d) 7/2

Ans. (c)

Ques. When NaCl is dissolved in water the sodium ion becomes?
(a) Oxidised
(b) Reduced
(c) Hydrolysed
(d) Hydrated

Ans. (d)

Ques. To prevent rancidification of food material, which of the following is added
(a) Reducing agent
(b) Anti-oxidant
(c) Oxidising agent
(d) None of these

Ans. (b)

Related: Surface chemistry questions

Ques. HNO₂ acts both as reductant and oxidant, while HNO₃ acts only as oxidant. It is due to their
(a) Solubility ability
(b) Maximum oxidation number
(c) Minimum oxidation number
(d) Minimum number of valence electrons

Ans. (b)

Ques. The oxidation number of As is
(a) + 2 and + 3
(b) + 3 and + 5
(c) + 3 and + 4
(d) None of these

Ans. (b)

Ques. The oxidation state of nitrogen in N₃H is
(a) + 1/3
(b) + 3
(c) -1
(d) – 1/3

Ans. (d)

Ques. The oxidation number of C in CO₂is
(a) – 2
(b) + 2
(c) – 4
(d) + 4

Ans. (d)