Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : An aqueous solution of KOH when for volumetric analysis, its concentration should be checked before the use. Reason (R) : On aging, KOH solution absorbs atmospheric CO 2 . In the light of the above statements, choose the correct answer from the options given below.

Both (A) and (R) are correct and (R) is the correct explanation of (A)

(A) is not correct but (R) is correct

Both (A) and (R) are correct but (R) is not the correct explanation of (A)

(A) is correct but (R) is not correct

Incorrect statement for the use of indicator in acid-base titration is:

Methyl orange may be used for a weak acid vs weak bas titration.

Phenolphthalein may be used for a strong acid vs strong base titration.

Methyl orange is a suitable indicator for a strong acid vs weak base titration.

Phenolphthalein is a suitable indicator for a weak acid vs strong base titration.

When Cu 2 + ion is treated with KI , a white precipitate, X appears in solution. The solution is titrated with sodium thiosulphate, the compound Y is formed. X and Y respectively are

X = Cu 2 I 2 , Y = Na 2 S 4 O 6

X = Cu 2 I 2 , Y = Na 2 S 4 O 5

In which of the following reactions the hydrogen peroxide acts as a reducing agent?

HOCl + H 2 O 2 → H 3 O + + Cl - 1 + O 2

PbS + 4 H 2 O 2 → PbSO 4 + 4 H 2 O

2 Fe 2 + + H 2 O 2 → 2 Fe 3 + + 2 OH -

Mn 2 + + H 2 O 2 → Mn 4 + + 2 OH -

EASY

JEE Main

IMPORTANT

Earn 100

In mildly alkaline medium, thiosulphate ion is oxidized by ${MnO}_{4}^{-}$ to $" A "$ . The oxidation state of sulphur in $" A "$ is_

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Important Questions on Redox Reactions

MEDIUM

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR CHEMISTRY>Chapter 6 - Redox Reactions>JEE Main - 26 August 2021 Shift 1>Q 23

Given below are two statements:
Statement I : In the titration between strong acid and weak base methyl orange is suitable as an indicator.
Statement II : For titration of acetic acid with $\mathrm{NaOH}$ phenolphthalein is not a suitable indicator.
In the light of the above statements, choose the most appropriate answer from the options given below:

EASY

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR CHEMISTRY>Chapter 6 - Redox Reactions>JEE Main - 25 July 2021 Shift 1>Q 24

When

10 mL

of an aqueous solution of

{Fe}^{2 +}

ions was titrated in the presence of dil

H_{2} {SO}_{4}

using diphenylamine indicator,

15 mL

0.02 M

solution of

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

was required to get the end point. The molarity of the solution containing

{Fe}^{2 +}

ions is

x \times 10^{- 2} M

. The value of

x

is ______. (Nearest integer)

EASY

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR CHEMISTRY>Chapter 6 - Redox Reactions>JEE Main - 25 Feb 2021 Shift 1>Q 25

Which of the following equation depicts the oxidizing nature of

H_{2} O_{2}

HARD

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR CHEMISTRY>Chapter 6 - Redox Reactions>JEE Main - 25 Feb 2021 Shift 1>Q 26

0.4 g

mixture of

NaOH, {Na}_{2} {CO}_{3}

and some inert impurities was first titrated with

\frac{N}{10} HCl

using phenolphthalein as an indicator,

17.5 mL

HCl

was required at the end point. After this methyl orange was added and titrated.

1.5 mL

of same

HCl

was required for the next end point. The weight percentage of

{Na}_{2} {CO}_{3}

in the mixture is (Rounded-off to the nearest integer)

MEDIUM

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR CHEMISTRY>Chapter 6 - Redox Reactions>JEE Main - 25 Feb 2021 Shift 1>Q 27

In basic medium

{CrO}_{4}^{2 -}

oxidises

S_{2} O_{3}^{2 -}

to form

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

and itself changes into

Cr {(OH)}_{4}^{-}

.The volume of

0.154 {MCrO}_{4}^{2 -}

required to react with

40 mL

0.25 {MS}_{2} {O_{3}}^{2 -}

is _____

mL .

(Rounded-off to the nearest integer)

EASY

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR CHEMISTRY>Chapter 6 - Redox Reactions>JEE Main - 24 Feb 2021 Shift 1>Q 28

The electrode potential of

M^{2 +} / M

3

d-series elements shows positive value for?

HARD

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR CHEMISTRY>Chapter 6 - Redox Reactions>JEE Main - 24 Feb 2021 Shift 1>Q 29

The reaction of sulphur in alkaline medium is given below:

$S_{8 (s)} + a {OH}_{(aq)}^{-} \to b S_{(aq)}^{2 -} + c S_{2} O_{3 (aq)}^{2 -} + d H_{2} O_{(l)}$

The values of ' $a$ ' is______ (Integer answer)

EASY

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR CHEMISTRY>Chapter 6 - Redox Reactions>JEE Main - 20 July 2021 Shift 1>Q 30

The species given below that does

NOT

show disproportionation reaction is:

In mildly alkaline medium, thiosulphate ion is oxidized by MnO4- to "A". The oxidation state of sulphur in "A" is_

Important Questions on Redox Reactions

Learn and Prepare for any exam you want !

In mildly alkaline medium, thiosulphate ion is oxidized by ${MnO}_{4}^{-}$ to $" A "$ . The oxidation state of sulphur in $" A "$ is_