Redox Reactions : Chemistry MCQ Practice Questions & Answers (Urdu)

ChemistryEasyRedox Reactions

1.

The oxidation state of Cr in Cr (CO)6 is

A

0

B

2

C

4

D

6

ChemistryEasyRedox Reactions

2.

For the feasibility of redox reaction in a cell, the e.m.f. should be

A

Positive

B

Fixed

C

Zero

D

Negative

ChemistryEasyRedox Reactions

3.

The oxide, which cannot act as a reducing agent is

A

$CO_2$

B

$ClO_2$

C

$NO_2$

D

$SO_2$

ChemistryEasyRedox Reactions

4.

Oxidation state of Fe in $Fe_3O_4$ is

A

5/4

B

4/5

C

3/2

D

8/3

ChemistryEasyRedox Reactions

5.

Oxidation numbers of P in $PO_4^{3-}$ , of S in $SO_4^{2-}$ and that of Cr in $Cr_2O_7^{2-}$ are respectively

A

+3, +6 and +5

B

+5, +3 and +6

C

–3, +6 and +6

D

+5, +6 and +6

ChemistryEasyRedox Reactions

6.

What is n-factor?

A

Equal to product of Number of moles of electrons when Lost or gained by one mole of reductant or oxidant

B

When Number of moles of electrons Lost or gained by one mole of reductant or oxidant is not same.

C

Equal to Number of moles of electrons Lost or gained by one mole of reductant or oxidant

D

None of the above

ChemistryEasyRedox Reactions

7.

The tendency of an electrode to lose electrons is known as

A

Electrode Potential

B

Reduction Potential

C

Oxidation Potential

D

E.M.F.

ChemistryEasyRedox Reactions

8.

What is known as Autooxidation?

A

Formation of $H_2O$ by the oxidation of $H_2O_2$

B

Formation of $H_2O_2$ by the oxidation of $H_2O$

C

Both (1) and (2) are true

D

None of the above

ChemistryEasyRedox Reactions

9.

Which of the following elements does not show disproportionation tendency?

A

Cl

B

Br

C

F

D

I

ChemistryEasyRedox Reactions

10.

The largest oxidation number exhibited by an element depends on its outer electronic configuration. With which of the following outer electronic configurations the element will exhibit largest oxidation number?

A

3d14s2

B

3d2 4s2

C

3d54s1

D

3d54s2

ChemistryEasyRedox Reactions

11.

The oxidation number of an element in a compound is evaluated on the basis of certain rules. Which of the following rules is not correct in this respect?

A

The oxidation number of hydrogen is always +1.

B

The algebraic sum of all the oxidation numbers in a compound is zero.

C

An element in the free or the uncombined state bears oxidation number zero.

D

In all its compounds, the oxidation number of fluorine is -1.

ChemistryEasyRedox Reactions

12.

Which reaction is not feasible?

A

2KI + $Br_2$ -> 2KBr + $I_2$

B

2KBr + $I_2$ -> 2KI + $Br_2$

C

2KBr + $Cl_2$ -> 2KCl+ $Br_2$

D

2H2O + 2F2 -> 4HF+ $O_2$

ChemistryEasyRedox Reactions

13.

Which of the following is a redox reaction?

A

$NaCl$ + $KNO_3$ -> $NaNO_3$ + $KCl$

B

$CaC_2O_4$ + 2HCl -> $CaCl_2$ + $H_2C_2O_4$

C

Mg (OH)2 + 2NH4Cl -> $MgCl_2$ + 2NH4OH

D

Zn + 2AgCN -> 2Ag + Zn (CN)2

ChemistryEasyRedox Reactions

14.

In oxygen di fluoride the oxidation number of oxygen is

A

-2

B

-1

C

2

D

+1, -2

ChemistryEasyRedox Reactions

15.

The oxidation number of Sulphur in $Na_2S_4O_6$ is

A

1.5

B

2.5

C

3

D

2

ChemistryEasyRedox Reactions

16.

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

A

3

B

6

C

-3

ChemistryEasyRedox Reactions

17.

The oxidation number of Cl in $Cl_2O_7$ is

A

+7

B

5

C

3

D

-7

ChemistryEasyRedox Reactions

18.

Which of the following processes does not involve either oxidation or reduction?

A

Formation of slaked lime from quick lime

B

Heating Mercuric Oxide

C

Formation of Manganese Chloride from Manganese oxide

D

Formation of Zinc from Zinc blende

ChemistryEasyRedox Reactions

19.

Which of the following processes does not involve oxidation of iron?

A

Formation of Fe (CO)5 from Fe.

B

Liberation of $H_2$ from steam by iron at high temperature.

C

Rusting of iron sheets.

D

Decolorization of blue $CuSO_4$ solution by iron.

ChemistryEasyRedox Reactions

20.

The number of moles of $KMnO_4$ reduced by one mole of KI in alkaline medium is

A

One

B

Two

C

Five

D

One fifth

Redox Reactions in Chemistry : Practice MCQ Questions & Answers with Explanations