HARD

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$1.5 gm$ of $KI$ is reacted with excess of ${KIO}_{3}$ to produce $I_{2}$ which is reacted with ${Na}_{2} S_{2} O_{3}$ in basic medium, where ${Na}_{2} S_{2} O_{3}$ converts to ${SO}_{4}^{2 -}$ . If the strength of ${Na}_{2} S_{2} O_{3}$ is $\frac{M}{10}$ , then the volume of ${Na}_{2} S_{2} O_{3}$ needed to reach equivalence point is:

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Important Questions on Redox Reactions

HARD

Chemistry>Physical Chemistry>Redox Reactions>Volumetric Analysis

To measure the quantity of

{MnCl}_{2}

dissolved in an aqueous solution, it was completely converted to

{KMnO}_{4}

using the reaction,

{MnCl}_{2} + K_{2} S_{2} O_{8} + H_{2} O \to {KMnO}_{4} + H_{2} {SO}_{4} + HCl

(equation not balanced). Few drops of concentrated

HCl

were added to this solution and gently warmed. Further, oxalic acid

(225 mg)

) was added in portions till the colour of the permanganate ion disappeared. What is the quantity of

{MnCl}_{2}

(in mg) present in the initial solution? (Atomic weights in

g {mol}^{- 1} : Mn = 55, Cl = 35 .5

)

HARD

Chemistry>Physical Chemistry>Redox Reactions>Volumetric Analysis

For kinetic study of the reaction of iodide ion with $H_{2} O_{2}$ at room temperature :

(A) Always use freshly prepared starch solution.

(B) Always keep the concentration of sodium thiosulphate solution less than that of $KI$ solution.

(D) Record the time immediately before the appearance of blue colour.

(E) Always keep the concentration of sodium thiosulphate solution more than that of $KI$ solution.

Choose the correct answer from the options given below

MEDIUM

Chemistry>Physical Chemistry>Redox Reactions>Volumetric Analysis

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

MEDIUM

Chemistry>Physical Chemistry>Redox Reactions>Volumetric Analysis

For standardizing

NaOH

solution, which of the following is used as a primary standard?

EASY

Chemistry>Physical Chemistry>Redox Reactions>Volumetric Analysis

In the given chemical reaction, colors of the ${Fe}^{2 +}$ and ${Fe}^{3 +}$ ions, are respectively :

$5 {Fe}^{2 +} + {MnO}_{4}^{-} + 8 H^{+} \to {Mn}^{2 +} + 4 H_{2} O + 5 {Fe}^{3 +}$

MEDIUM

Chemistry>Physical Chemistry>Redox Reactions>Volumetric Analysis

50 mL

0 .5 M

oxalic acid is needed to neutralize

25 mL

of sodium hydroxide solution. What is the amount of

NaOH

50 mL

of the given sodium hydroxide solution?

MEDIUM

Chemistry>Physical Chemistry>Redox Reactions>Volumetric Analysis

An indicator ‘

X

’ is used for studying the effect of variation in concentration of iodide on the rate of reaction of iodide ion with

H_{2} O_{2}

at room temp. The indicator ‘

X

’ forms blue colored complex with compound ‘

A

’ present in the solution. The indicator ‘

X

’ and compound ‘

A

’ respectively are

EASY

Chemistry>Physical Chemistry>Redox Reactions>Volumetric Analysis

While titration dilute

HCl

solution with aqueous

NaOH

, which of the following will not be required ?

MEDIUM

Chemistry>Physical Chemistry>Redox Reactions>Volumetric Analysis

Excess of acidic solution of

KI

to mixed with

25 mL

H_{2} O_{2}

. Liberated

I_{2}

requires

20 mL

0.3 N {Na}_{2} S_{2} O_{3}

solution. The volume strength of

H_{2} O_{2}

HARD

Chemistry>Physical Chemistry>Redox Reactions>Volumetric Analysis

2.0 g

sample containing

{MnO}_{2}

is treated with

HCl

liberating

{Cl}_{2}

. The

{Cl}_{2}

gas is passed into a solution of

KI

and

60.0 mL

0.1 {MNaS}_{2} O_{3}

is required to titrate the liberated iodine. The percentage of

{MnO}_{2}

in the sample is____. Nearest integer)
[Atomic masses (in

u

)

Mn = 55; Cl = 35.5 : O = 16, I = 127, Na = 23, K = 39, S = 32

]

HARD

Chemistry>Physical Chemistry>Redox Reactions>Volumetric Analysis

In a complexometric titration of metal ion with ligand

M (M e t a l i o n) + L (L i g a n d) \to C (C o m p l e x)

end point is estimated spectrophotometrically (through light absorption). If 'M' and 'C' do not absorb light and only 'L' absorbs then the titration plot between absorbed light

(A)

versus volume of ligand 'L'

(V)

would look like:

HARD

Chemistry>Physical Chemistry>Redox Reactions>Volumetric Analysis

Identify the correct statements from the following.
i.In

{[CoCl {({NH}_{3})}_{5}]}^{2 +},

the Lewis acid is

{Co}^{3 +}

ii. An example for heteroleptic complex is

{[Co {({NH}_{3})}_{6}]}^{3 +}

iii. The hybridisation of

Mn

{[{MnBr}_{4}]}^{2 -}

{dsp}^{2}

iv. In

[Ni (CO)_{4}],

the metal-carbon bond possesses

σ

and

π

character.

MEDIUM

Chemistry>Physical Chemistry>Redox Reactions>Volumetric Analysis

An alkali is titrated against acid with methyl orange as an indicator, which of the following is a correct combination?

HARD

Chemistry>Physical Chemistry>Redox Reactions>Volumetric Analysis

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

MEDIUM

Chemistry>Physical Chemistry>Redox Reactions>Volumetric Analysis

The strength of an aqueous

N a O H

solution is most accurately determined by titrating: (Note: consider that an appropriate indicator is used)

MEDIUM

Chemistry>Physical Chemistry>Redox Reactions>Volumetric Analysis

2 {KMnO}_{4} + 3 H_{2} {SO}_{4} + 5 H_{2} O_{2} \to K_{2} {SO}_{4} + 2 {MnSO}_{4} + 8 H_{2} O + 5 O_{2}

Find the nonnality of

H_{2} O_{2}

solution, if

20 mL

of it is required to react completely with

16 mL

0.02 {MKMnO}_{4}

solution. ( Molar mass of

{KMnO}_{4} = 158 g {mol}^{- 1}

)

MEDIUM

Chemistry>Physical Chemistry>Redox Reactions>Volumetric Analysis

In the titration of

I_{2} (aq)

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

(aq)

using the starch indicator, the end point is indicated by:

MEDIUM

Chemistry>Physical Chemistry>Redox Reactions>Volumetric Analysis

0.01 {MKMnO}_{4}

solution was added to

20.0 mL

0.05 M Mohr

's salt solution through a burette. The initial reading of

50 mL

burette is zero. The volume of

{KMnO}_{4}

solution left in the burette after the end point is.......

mL

. (nearest integer)

HARD

Chemistry>Physical Chemistry>Redox Reactions>Volumetric Analysis

In a titration experiment, $10 mL$ of an ${FeCl}_{2}$ solution consumed $25 mL$ of a standard $K_{2} {Cr}_{2} O_{7}$ solution to reach the equivalent point. The standard $K_{2} {Cr}_{2} O_{7}$ solution is prepared by dissolving $1.225 g$ of $K_{2} {Cr}_{2} O_{7}$ in $250 mL$ water. The concentration of the ${FeCl}_{2}$ solution is closest to

[Given : molecular weight of $K_{2} {Cr}_{2} O_{7} = 294 g {mol}^{- 1}$ ]

HARD

Chemistry>Physical Chemistry>Redox Reactions>Volumetric Analysis

The volume of

0.1 {MKMnO}_{4}

solution required to completely react with a solution obtained by dissolving

0.63 g

of oxalic acid (molar mass

126 {gmol}^{- 1})

50 mL

distilled water in acidic medium in

mL

1.5 gm of KI is reacted with excess of KIO3 to produce I2 which is reacted with Na2S2O3 in basic medium, where Na2S2O3 converts to SO42-. If the strength of Na2S2O3 is M10, then the volume of Na2S2O3 needed to reach equivalence point is:

Important Questions on Redox Reactions

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