JEE Main Redox Reactions Practice Questions With Solutions

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JEE Main Chemistry Redox Reactions Practice Questions

Question 1.

Thiosulphate reacts differently with iodine and bromine in the reactions given below:

$\begin{aligned} 2 S_{2} O_{3}^{2 -} + I_{2} \to S_{4} O_{6}^{2 -} + 2 I^{-} \\ S_{2} O_{3}^{2 -} + 5 {Br}_{2} + 5 H_{2} O \to 2 {SO}_{4}^{2 -} + 4 {Br}^{-} + 10 H^{+} \end{aligned}$

Which of the following statement justifies the above dual behaviour of thiosulphate?

Thiosulphate undergoes oxidation by bromine and reduction by iodine in these reactions

Bromine is a weaker oxidant than iodine

Bromine is a stronger oxidant than iodine

Bromine undergoes oxidation and iodine undergoes reduction in these reactions

Question 2.

The number of ions from the following that are expected to behave as oxidising agent is :

${Sn}^{4 +}, {Sn}^{2 +}, {Pb}^{2 +}, {Tl}^{3 +}, {Pb}^{4 +}, {Tl}^{+}$

Question 3.

Match List I with List II.

	LIST I Reaction		LIST II Type of redox reaction
A.	$N_{2 (g)} + O_{2 (g)} \to 2 {NO}_{(g)}$	I.	Decomposition
B.	$2 Pb {({NO}_{3})}_{2 (s)} \to 2 {PbO}_{(s)} + 4 {NO}_{2 (g)} + O_{2 (g)}$	II.	Displacement
C.	$2 {Na}_{(s)} + 2 H_{2} O_{(l)} \to 2 {NaOH}_{(aq .)} + H_{2 (g)}$	III.	Disproportionation
D.	$2 {NO}_{2 (g)} + 2^{-} OH (aq.) \to {NO}_{2 (aq .)}^{-} + {NO}_{3 (aq.)}^{-} + H_{2} O_{(l)}$	IV.	Combination

Choose the correct answer from the options given below :

(A)-(IV), (B)-(I), (C)-(II), (D)-(III)

(A)-(I), (B)-(II), (C)-(III), (D)-(IV)

(A)-(II), (B)-(III), (C)-(IV), (D)-(I)

(A)-(III), (B)-(II), (C)-(I), (D)-(IV)

Question 4.

When ${MnO}_{2}$ and $H_{2} {SO}_{4}$ is added to a salt $(A)$ , the greenish yellow gas liberated as salt (A) is :

{NH}_{4} Cl

{CaI}_{2}

{KNO}_{3}

NaBr

Question 5.

Which of the following reactions are disproportionation reactions?

(A)

{Cu}^{+} \to {Cu}^{2 +} + Cu

(B)

3 {MnO}_{4}^{2 -} + 4 H^{+} ⟶ 2 {MnO}_{4}^{-} + {MnO}_{2} + 2 H_{2} O

(C)

2 {KMnO}_{4} ⟶ K_{2} {MnO}_{4} + {MnO}_{2} + O_{2}

(D)

2 {MnO}_{4}^{-} + 3 {Mn}^{2 +} + 2 H_{2} O ⟶ 5 {MnO}_{2} + 4 H^{+}

Choose the correct answer from the options given below :

(A), (B)

(A), (D)

(B), (C), (D)

(A), (B), (C)

Question 6.

In acidic medium,

K_{2} {Cr}_{2} O_{7}

shows oxidising action as represented in the half reaction:

{Cr}_{2} O_{7}^{2 -} + {XH}^{+} + {Ye}^{⊖} \to 2 A + {ZH}_{2} O

X, Y, Z

and

A

are respectively are :

14, 7, 6

and

{Cr}^{3 +}

14, 6, 7

and

{Cr}^{3 +}

8, 4, 6

and

{Cr}_{2} O_{3}

8, 6, 4

and

{Cr}_{2} O_{3}

Question 7.

Chlorine undergoes disproportionation in alkaline medium as shown below :

${aCl}_{2 (g)} + b {OH}_{(aq)}^{-} \to c {ClO}_{(aq)}^{-} + d {Cl}_{(aq)}^{-} + e H_{2} O_{(l)}$

The values of $a, b, c$ and $d$ in a balanced redox reaction are respectively :

3, 4, 4 and 2

1, 2, 1 and 1

2, 4, 1 and 3

2, 2, 1 and 3

Question 8.

In alkaline medium, ${MnO}_{4}^{-}$ oxidises $I^{-}$ to

I_{2}

{IO}_{3}^{-}

{IO}^{-}

{IO}_{4}^{-}

Question 9.

Which of the following cannot function as an oxidising agent?

{SO}_{4}^{2 -}

{MnO}_{4}^{-}

N^{3 -}

{BrO}_{3}^{-}

Question 10.

Given below are two statements:

Statement I : In redox titration, the indicators used are sensitive to change in $pH$ of the solution.

Statement II : In acid-base titration, the indicators used are sensitive to change in oxidation potential.

In the light of the above statements, choose the most appropriate answer from the options given below

Both Statement I and Statement II are incorrect

Statement I is correct but Statement II is incorrect

Statement I is incorrect but Statement II is correct

Both Statement I and Statement II are correct

Question 1.

$2 {IO}_{3}^{-} + x I^{-} + 12 H^{+} \to 6 I_{2} + 6 H_{2} O$

What is the value of $x$ ?

Question 2.

Which of the following options are correct for the reaction

$2 {[Au (CN)_{2}]}^{-} (aq) + Zn (s) \to 2 Au (s) + {[Zn (CN)_{4}]}^{2 -} (aq)$

A. Redox reaction

B. Displacement reaction

C. Decomposition reaction

D. Combination reaction

Choose the correct answer from the options given below:

A and B only

C and D only

A only

A and D only

Question 3.

A compound 'X' is a weak acid and it exhibits colour change at pH close to the equivalence point during neutralization of NaOH with ${CH}_{3} COOH$ . Compound 'X' exists in ionized form in basic medium. The compound 'X' is

methyl orange

methyl red

phenolphthalein

erichrome Black T

Question 4.

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$ .

Assertion A: Phenolphthalein is a $pH$ dependent indicator, remains colourless in acidic solution and gives pink colour in basic medium.

Reason R: Phenolphthalein is a weak acid. It doesn't dissociate in basic medium.

In the light of the above statements, choose the most appropriate answer from the options given below.

Both

A

and

R

are true and

R

is the correct explanation of

A

Both

A

and

R

are true but

R

is NOT the correct explanation of

A

A is true but R is false.

A is false but R is true.

Question 5.

Which of the given reactions is not an example of disproportionation reaction?

2 H_{2} O_{2} \to 2 H_{2} O + O_{2}

2 {NO}_{2} + H_{2} O \to {HNO}_{3} + {HNO}_{2}

{MnO}_{4}^{-} + 4 H^{+} + 3 e^{-} \to {MnO}_{2} + 2 H_{2} O

3 {MnO}_{4}^{2 -} + 4 H^{+} \to 2 {MnO}_{4}^{-} + {MnO}_{2} + 2 H_{2} O

Question 6.

Which one of the following is an example of disproportionation reaction ?

3 M n O_{4}^{2 -} + 4 H^{+} \to 2 M n O_{4}^{-} + M n O_{2} + 2 H_{2} O

M n O_{4}^{-} + 4 H^{+} + 4 e^{-} \to M n O_{2} + 2 H_{2} O

10 I^{-} + 2 M n O_{4}^{-} + 16 H^{+} \to 2 M n^{2 +} + 8 H_{2} O + 5 I_{2}

8 M n O_{4}^{-} + 3 S_{2} O_{3}^{2 -} + H_{2} O \to 8 M n O_{2} + 6 S O_{4}^{2 -} + 2 O H^{-}

Question 7.

The oxidation states of 'P' in H₄P₂O₇, H₄P₂O₅ and H₄P₂O₆, respectively, are :

7, 5 and 6

5, 4 and 3

5, 3 and 4

6, 4 and 5

Question 8.

Identify the process in which change in the oxidation state is five :

C r_{2} O_{7}^{2 -} \to 2 C r^{3 +}

M n O_{4}^{-} \to M n^{2 +}

C r O_{4}^{2 -} \to C r^{3 +}

C_{2} O_{4}^{2 -} \to 2 C O_{2}

Question 9.

The oxidation states of nitrogen in NO, NO₂, N₂O and NO

_{3}^{-}

are in the order of :

N₂O > NO₂ > NO > NO

_{3}^{-}

NO > NO₂ > N₂O > NO

_{3}^{-}

NO₂ > NO

_{3}^{-}

> NO > N₂O

_{3}^{-}

> NO₂ > NO > N₂O

Question 10.

Statement I : Sodium hydride can be used as an oxidising agent.

Statement II : The lone pair of electrons on nitrogen in pyridine makes it basic.

Choose the CORRECT answer from the options given below :

Statement I is false but statement II is true

Both statement I and statement II are true

Statement I is true but statement II is false

Both statement I and statement II are false

JEE Main Redox Reactions Practice Questions With Solutions

JEE Main Chemistry Redox Reactions Practice Questions

Question 1.

Question 2.

Question 3.

Question 4.

Question 5.

Question 6.

Question 7.

Question 8.

Question 9.

Question 10.

Question 1.

Question 2.

Question 3.

Question 4.

Question 5.

Question 6.

Question 7.

Question 8.

Question 9.

Question 10.

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