MEDIUM

Earn 100

An impure sample of sodium oxalate $({Na}_{2} C_{2} O_{4})$ weighing $0.20 g$ is dissolved in an aqueous solution of $H_{2} {SO}_{4}$ . The solution is titrated at $70 ° C$ , requiring $45 mL$ of $0.02 M {KMnO}_{4}$ solution. The end point is overrun, and back titration in carried out with $10 mL$ of $0.1 M$ oxalic acid solution. Find the $%$ purity of ${Na}_{2} C_{2} O_{4}$ in the sample.

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Important Questions on Redox Reactions

MEDIUM

Chemistry>Physical Chemistry>Redox Reactions>Equivalent Concept

The volume, in

mL

, of

0.02 {MK}_{2} {Cr}_{2} O_{7}

, solution required to react with

0.288 g

of ferrous oxalate in acidic medium is

\dots \dots \dots \dots

(Molar mass of

Fe = 56 {gmol}^{- 1}

)

MEDIUM

Chemistry>Physical Chemistry>Redox Reactions>Equivalent Concept

The number of moles of electron required to reduce

0.2

mole of

{Cr}_{2} O_{7}^{- 2}

{Cr}^{+ 3}

EASY

Chemistry>Physical Chemistry>Redox Reactions>Equivalent Concept

The volume (in

mL

) of

0.1 N NaOH

required to neutralise

10 mL of 0.1 N

phosphinic acid is ____________.

MEDIUM

Chemistry>Physical Chemistry>Redox Reactions>Equivalent Concept

4 g

of copper was dissolved in

conc . {HNO}_{3}

. The copper nitrate thus obtained gave

5 g

of its oxide on strong heating the equivalent weight of copper is

MEDIUM

Chemistry>Physical Chemistry>Redox Reactions>Equivalent Concept

1 mol

F e S O_{4}

(a t o m i c w e i g h t o f F e i s 55.84 g m o l^{- 1})

is oxidized to

F e_{2} {(S O_{4})}_{3}

. Calculate the equivalent weight of ferrous ion

HARD

Chemistry>Physical Chemistry>Redox Reactions>Equivalent Concept

$5.00 mL$ of $0.10 M$ oxalic acid solution taken in a conical flask is titrated against $NaOH$ from a burette using phenolphthalein indicator. The volume of $NaOH$ required for the appearance of permanent faint pink colour is tabulated below for five experiments. The concentration, in molarity, of the $NaOH$ solution is $xM$ .

Exp. No.	Vol. of $NaOH$ $(mL)$
$1$	$12.5$
$2$	$10.5$
$3$	$9.0$
$4$	$9.0$
$5$	$9.0$

What is the value of $100 x$ ?

Round of your answer to the nearest integer.

MEDIUM

Chemistry>Physical Chemistry>Redox Reactions>Equivalent Concept

A $20.0 mL$ solution containing $0.2 g$ impure $H_{2} O_{2}$ reacts completely with $0.316 g$ of ${KMnO}_{4}$ in acid solution. The purity of $H_{2} O_{2}$ (in $%$ ) is______ (mol. wt. of $H_{2} O_{2} = 34$ ; mol. wt. of ${KMnO}_{4} = 158$ )

MEDIUM

Chemistry>Physical Chemistry>Redox Reactions>Equivalent Concept

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

Chemistry>Physical Chemistry>Redox Reactions>Equivalent Concept

The amount of

{Na}_{2} S_{2} O_{3} \cdot 5 H_{2} O

required to completely reduce 100 mL of 0.25 N iodine solution, is

EASY

Chemistry>Physical Chemistry>Redox Reactions>Equivalent Concept

The volume of 0.1 M strong dibasic acid sufficient to neutralize 1g of a base that furnishes 0.04 mole of

O H^{-}

in aqueous solution is :

MEDIUM

Chemistry>Physical Chemistry>Redox Reactions>Equivalent Concept

0.45 g

acid of molecular mass

90

was neutralise by

20

ml

0.5 N KOH

. The basicity of the acid is

MEDIUM

Chemistry>Physical Chemistry>Redox Reactions>Equivalent Concept

The number of electron required to reduce chromium completely in

{Cr}_{2} O_{7}^{2 -}

C r^{3 +}

in acidic medium, is

MEDIUM

Chemistry>Physical Chemistry>Redox Reactions>Equivalent Concept

A fuel cell generates electricity by using methanol as fuel and

O_{2}

as the oxidant. Calculate the equivalent weight of methanol.

MEDIUM

Chemistry>Physical Chemistry>Redox Reactions>Equivalent Concept

A $100 mL$ solution was made by adding $1.43 g$ of ${Na}_{2} {CO}_{3} . {xH}_{2} O .$ The normality of the solution is $0.1 N$ . The value of $x$ is _______

(The atomic mass of $Na$ is $23 g / mol$ )

EASY

Chemistry>Physical Chemistry>Redox Reactions>Equivalent Concept

How much

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

(molecular weight

= 294.19

) is required to prepare one litre of

0.1 N

solution ?

EASY

Chemistry>Physical Chemistry>Redox Reactions>Equivalent Concept

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

Chemistry>Physical Chemistry>Redox Reactions>Equivalent Concept

15 mL

of aqueous solution of

{Fe}^{2 +}

in acidic medium completely reacted with

20 mL

0.03 M

aqueous

{Cr}_{2} {O_{7}}^{2 -} .

The molarity of the

{Fe}^{2 +}

solution is _______

\times 10^{- 2} M

(Round off to the Nearest Integer).

MEDIUM

Chemistry>Physical Chemistry>Redox Reactions>Equivalent Concept

In order to oxidize a mixture of one mole of each of

F e C_{2} O_{4}, F e_{2} {(C_{2} O_{4})}_{3}, F e S O_{4}

and

F e_{2} {(S O_{4})}_{3}

in acidic medium, the number of moles of

K M n O_{4}

is:

MEDIUM

Chemistry>Physical Chemistry>Redox Reactions>Equivalent Concept

Complete reaction of 2.0 g of calcium (at wt. = 40) with excess

H C l

produces

1.125 L o f H_{2}

gas. Complete reaction of the same quantity of another metal "M" with excess

H C l

produces

1.85 L o f H_{2}

gas under identical conditions. The equivalent weight of "M" is closest to:

HARD

Chemistry>Physical Chemistry>Redox Reactions>Equivalent Concept

In the reaction of oxalate with permanganate in acidic medium, the number of electrons involved in producing one molecule of

{CO}_{2}

is:

Important Questions on Redox Reactions

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