QBManager

CHXII08:THE D- & F-BLOCK ELEMENTS

321318 Which ore is used for the preparation of ${KMnO}_{4}$ ?

1 Pyrolusite

2 Wolframite

3 Cerrusite

4 Casseterite

Explanation:

Pyrolusite is ${MnO}_{2}$ .

CHXII08:THE D- & F-BLOCK ELEMENTS

321319 Pyrolusite is ${MnO}_{2}$ , and is used to prepare ${KMnO}_{4.}$ The Steps are
${MnO}_{2} \overset{I}{\to} {MnO}_{4}^{2 -} \overset{II}{\to} {MnO}_{4}^{-}$
Steps I and II are respectively:

1 Fuse with

KOH /

air and electrolytic oxidation.

2 Fuse with

KOH / {KNO}_{3}

and electrolytic oxidation.

3 Both (1) and (2).

4 Dissolve in

H_{2} O

and oxidation.

Explanation:

${MnO}_{2}$ fused with $KOH$ in presence of air or oxidising agents like ${KNO}_{3}, {KClO}_{3}$ etc.
$2 {MnO}_{2} + 4 KOH + O_{2} \overset{fuse}{\to} 2 K_{2} {MnO}_{4} + 2 H_{2} O$
${MnO}_{4}^{2 -} \overset{electrolytic oxidation}{\to} {MnO}_{4}^{-} + e^{-}$

CHXII08:THE D- & F-BLOCK ELEMENTS

321320 Name the gas that can readily decolourise acidified ${KMnO}_{4}$ solution:

1

{SO}_{2}

2

{NO}_{2}

3

P_{2} O_{5}

4

{CO}_{2}

Explanation:

$\overset{+ 7}{K M n O_{4}} + \overset{+ 4}{S O_{2}} \to M n S O_{4} + H_{2} S O_{4} + K_{2} S O_{4}$
$(O . A) (R . A) (c o l o u r l e s s)$

NEET - 2017

CHXII08:THE D- & F-BLOCK ELEMENTS

321321 ${KMnO}_{4}$ decomposes on heating at 513 K to form $O_{2}$ along with

1

K_{2} {MnO}_{4}

and

{MnO}_{2}

2 Mn and

{KO}_{2}

3

{MnO}_{2}

and

K_{2} O_{2}

4

K_{2} {MnO}_{4}

and Mn

Explanation:

$2 {KMnO}_{4} \overset{513 K}{\to} K_{2} {MnO}_{4} + {MnO}_{2} + O_{2}$
So, the correct option is (1).

JEE Main - 2024

CHXII08:THE D- & F-BLOCK ELEMENTS

321318 Which ore is used for the preparation of ${KMnO}_{4}$ ?

1 Pyrolusite

2 Wolframite

3 Cerrusite

4 Casseterite

Explanation:

Pyrolusite is ${MnO}_{2}$ .

CHXII08:THE D- & F-BLOCK ELEMENTS

321319 Pyrolusite is ${MnO}_{2}$ , and is used to prepare ${KMnO}_{4.}$ The Steps are
${MnO}_{2} \overset{I}{\to} {MnO}_{4}^{2 -} \overset{II}{\to} {MnO}_{4}^{-}$
Steps I and II are respectively:

1 Fuse with

KOH /

air and electrolytic oxidation.

2 Fuse with

KOH / {KNO}_{3}

and electrolytic oxidation.

3 Both (1) and (2).

4 Dissolve in

H_{2} O

and oxidation.

Explanation:

${MnO}_{2}$ fused with $KOH$ in presence of air or oxidising agents like ${KNO}_{3}, {KClO}_{3}$ etc.
$2 {MnO}_{2} + 4 KOH + O_{2} \overset{fuse}{\to} 2 K_{2} {MnO}_{4} + 2 H_{2} O$
${MnO}_{4}^{2 -} \overset{electrolytic oxidation}{\to} {MnO}_{4}^{-} + e^{-}$

CHXII08:THE D- & F-BLOCK ELEMENTS

321320 Name the gas that can readily decolourise acidified ${KMnO}_{4}$ solution:

1

{SO}_{2}

2

{NO}_{2}

3

P_{2} O_{5}

4

{CO}_{2}

Explanation:

$\overset{+ 7}{K M n O_{4}} + \overset{+ 4}{S O_{2}} \to M n S O_{4} + H_{2} S O_{4} + K_{2} S O_{4}$
$(O . A) (R . A) (c o l o u r l e s s)$

NEET - 2017

CHXII08:THE D- & F-BLOCK ELEMENTS

321321 ${KMnO}_{4}$ decomposes on heating at 513 K to form $O_{2}$ along with

1

K_{2} {MnO}_{4}

and

{MnO}_{2}

2 Mn and

{KO}_{2}

3

{MnO}_{2}

and

K_{2} O_{2}

4

K_{2} {MnO}_{4}

and Mn

Explanation:

$2 {KMnO}_{4} \overset{513 K}{\to} K_{2} {MnO}_{4} + {MnO}_{2} + O_{2}$
So, the correct option is (1).

JEE Main - 2024

CHXII08:THE D- & F-BLOCK ELEMENTS

321318 Which ore is used for the preparation of ${KMnO}_{4}$ ?

1 Pyrolusite

2 Wolframite

3 Cerrusite

4 Casseterite

Explanation:

Pyrolusite is ${MnO}_{2}$ .

CHXII08:THE D- & F-BLOCK ELEMENTS

321319 Pyrolusite is ${MnO}_{2}$ , and is used to prepare ${KMnO}_{4.}$ The Steps are
${MnO}_{2} \overset{I}{\to} {MnO}_{4}^{2 -} \overset{II}{\to} {MnO}_{4}^{-}$
Steps I and II are respectively:

1 Fuse with

KOH /

air and electrolytic oxidation.

2 Fuse with

KOH / {KNO}_{3}

and electrolytic oxidation.

3 Both (1) and (2).

4 Dissolve in

H_{2} O

and oxidation.

Explanation:

${MnO}_{2}$ fused with $KOH$ in presence of air or oxidising agents like ${KNO}_{3}, {KClO}_{3}$ etc.
$2 {MnO}_{2} + 4 KOH + O_{2} \overset{fuse}{\to} 2 K_{2} {MnO}_{4} + 2 H_{2} O$
${MnO}_{4}^{2 -} \overset{electrolytic oxidation}{\to} {MnO}_{4}^{-} + e^{-}$

CHXII08:THE D- & F-BLOCK ELEMENTS

321320 Name the gas that can readily decolourise acidified ${KMnO}_{4}$ solution:

1

{SO}_{2}

2

{NO}_{2}

3

P_{2} O_{5}

4

{CO}_{2}

Explanation:

$\overset{+ 7}{K M n O_{4}} + \overset{+ 4}{S O_{2}} \to M n S O_{4} + H_{2} S O_{4} + K_{2} S O_{4}$
$(O . A) (R . A) (c o l o u r l e s s)$

NEET - 2017

CHXII08:THE D- & F-BLOCK ELEMENTS

321321 ${KMnO}_{4}$ decomposes on heating at 513 K to form $O_{2}$ along with

1

K_{2} {MnO}_{4}

and

{MnO}_{2}

2 Mn and

{KO}_{2}

3

{MnO}_{2}

and

K_{2} O_{2}

4

K_{2} {MnO}_{4}

and Mn

Explanation:

$2 {KMnO}_{4} \overset{513 K}{\to} K_{2} {MnO}_{4} + {MnO}_{2} + O_{2}$
So, the correct option is (1).

JEE Main - 2024

CHXII08:THE D- & F-BLOCK ELEMENTS

321318 Which ore is used for the preparation of ${KMnO}_{4}$ ?

1 Pyrolusite

2 Wolframite

3 Cerrusite

4 Casseterite

Explanation:

Pyrolusite is ${MnO}_{2}$ .

CHXII08:THE D- & F-BLOCK ELEMENTS

321319 Pyrolusite is ${MnO}_{2}$ , and is used to prepare ${KMnO}_{4.}$ The Steps are
${MnO}_{2} \overset{I}{\to} {MnO}_{4}^{2 -} \overset{II}{\to} {MnO}_{4}^{-}$
Steps I and II are respectively:

1 Fuse with

KOH /

air and electrolytic oxidation.

2 Fuse with

KOH / {KNO}_{3}

and electrolytic oxidation.

3 Both (1) and (2).

4 Dissolve in

H_{2} O

and oxidation.

Explanation:

${MnO}_{2}$ fused with $KOH$ in presence of air or oxidising agents like ${KNO}_{3}, {KClO}_{3}$ etc.
$2 {MnO}_{2} + 4 KOH + O_{2} \overset{fuse}{\to} 2 K_{2} {MnO}_{4} + 2 H_{2} O$
${MnO}_{4}^{2 -} \overset{electrolytic oxidation}{\to} {MnO}_{4}^{-} + e^{-}$

CHXII08:THE D- & F-BLOCK ELEMENTS

321320 Name the gas that can readily decolourise acidified ${KMnO}_{4}$ solution:

1

{SO}_{2}

2

{NO}_{2}

3

P_{2} O_{5}

4

{CO}_{2}

Explanation:

$\overset{+ 7}{K M n O_{4}} + \overset{+ 4}{S O_{2}} \to M n S O_{4} + H_{2} S O_{4} + K_{2} S O_{4}$
$(O . A) (R . A) (c o l o u r l e s s)$

NEET - 2017

CHXII08:THE D- & F-BLOCK ELEMENTS

321321 ${KMnO}_{4}$ decomposes on heating at 513 K to form $O_{2}$ along with

1

K_{2} {MnO}_{4}

and

{MnO}_{2}

2 Mn and

{KO}_{2}

3

{MnO}_{2}

and

K_{2} O_{2}

4

K_{2} {MnO}_{4}

and Mn

Explanation:

$2 {KMnO}_{4} \overset{513 K}{\to} K_{2} {MnO}_{4} + {MnO}_{2} + O_{2}$
So, the correct option is (1).

JEE Main - 2024