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CHXII08:THE D- & F-BLOCK ELEMENTS

321292 Which of the following statement is false?

1

{Na}_{2} {Cr}_{2} O_{7}

is less soluble than

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

2

{CrO}_{7}^{2 -}

has a

Cr - O - Cr

bond.

3

{Na}_{2} {Cr}_{2} O_{7}

is primary standard in volumetry.

4

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

is tetrahedral in shape.

Explanation:

supporting img

${Na}_{2} {Cr}_{2} O_{7}$ is used as primary standard in volumetry. Hydration energy of ${Na}^{\oplus}$ is greater than $K^{\oplus}$ .
Because of smaller size of ${Na}^{\oplus}, {Na}_{2} {Cr}_{2} O_{7}$ is more soluble than $K_{2} {Cr}_{2} O_{7}$ .

JEE - 2015

CHXII08:THE D- & F-BLOCK ELEMENTS

321293 How many moles of stannic chloride can be formed when excess stannous chloride reacts with 1 mole of potassium dichromate in acidic medium?

1 1

2 2

3 3

4 6

Explanation:

$3 {Sn}^{+ 2} + {Cr}_{2} O_{7}^{- 2} + 14 H^{+} \to$
$3 S n^{+ 4} + 2 C r^{+ 3} + 7 H_{2} O$
So, 1 mole $K_{2} {Cr}_{2} O_{7}$ oxidises 3 moles of ${SnCl}_{2}$ to ${SnCl}_{4}$ .

CHXII08:THE D- & F-BLOCK ELEMENTS

321294 A white crystalline salt A reacts with dilute $HCl$ to liberate a suffocating gas B and also forms a yellow precipitate. The gas $B$ turns potassium dichromate acidified with dilute $H_{2} {SO}_{4}$ to a green coloured solution C. A, B and C are respectively

1

{Na}_{2} {SO}_{3}, {SO}_{2}, {Cr}_{2} {({SO}_{4})}_{3}

2

{Na}_{2} S_{2} O_{3}, {SO}_{2}, {Cr}_{2} {({SO}_{4})}_{3}

3

{Na}_{2} S, {SO}_{2}, {Cr}_{2} {({SO}_{4})}_{3}

4

{Na}_{2} {SO}_{4}, {SO}_{2}, {Cr}_{2} {({SO}_{4})}_{3}

Explanation:

Dil.HCl decomposes ${Na}_{2} S_{2} O_{3} (A)$ with evolution of a gas which possesses a suffocating smell of burning sulphur i.e., ${SO}_{2} (B)$ and yellow ppt. of sulphur is obtained.
$N a_{2} S_{2} O_{3} + 2 H C l \to 2 N a C l + S O_{2} ↑ + S ↓ + H_{2} O$
$(A) (B) (Y e l l o w p p t .)$
When acidified potassium dichromate paper is exposed to the gas, it attains a green colour due to the formation of chromium sulphate.
$K_{2} C r_{2} O_{7} + H_{2} S O_{4} + 3 S O_{2} \to$
$K_{2} S O_{4} + C r_{2} (S O_{4})_{3} + H_{2} O$
$(C)$
$G r e e n$

KCET - 2010

CHXII08:THE D- & F-BLOCK ELEMENTS

321295 The oxidation state of chromium in the final product formed by the reaction between $KI$ and acidified potassium dichromate solution is

1 +3

2 +2

3 +6

4 +4

Explanation:

${Cr}_{2} O_{7}^{2 -} + 14 H^{+} + 6 I^{-} \to 2 {Cr}^{3 +} + 7 H_{2} O + 3 I_{2}$
Thus, oxidation state of $Cr$ in product is +3 .

AIIMS - 2012

CHXII08:THE D- & F-BLOCK ELEMENTS

321296 Yellow compound of lead chromate gets dissolved on treatment with hot $NaOH$ solution. The product of lead formed is a :

1 Tetraanionic complex with coordination number six.

2 Neutral complex with coordination number four.

3 Dianionic complex with coordination number six.

4 Dianionic complex with coordination number four.

Explanation:

Yellow ppt. of ${PbCrO}_{4} ↓$ is soluble in hot $NaOH$ , forming ${[Pb (OH)_{4}]}^{2 -}$ , as ${Pb}^{2 +}$ is amphoteric in nature. ${[Pb (OH)_{4}]}^{2 -}$ is divalent with coordination number 4 .

JEE - 2024

CHXII08:THE D- & F-BLOCK ELEMENTS

321292 Which of the following statement is false?

1

{Na}_{2} {Cr}_{2} O_{7}

is less soluble than

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

2

{CrO}_{7}^{2 -}

has a

Cr - O - Cr

bond.

3

{Na}_{2} {Cr}_{2} O_{7}

is primary standard in volumetry.

4

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

is tetrahedral in shape.

Explanation:

supporting img

${Na}_{2} {Cr}_{2} O_{7}$ is used as primary standard in volumetry. Hydration energy of ${Na}^{\oplus}$ is greater than $K^{\oplus}$ .
Because of smaller size of ${Na}^{\oplus}, {Na}_{2} {Cr}_{2} O_{7}$ is more soluble than $K_{2} {Cr}_{2} O_{7}$ .

JEE - 2015

CHXII08:THE D- & F-BLOCK ELEMENTS

321293 How many moles of stannic chloride can be formed when excess stannous chloride reacts with 1 mole of potassium dichromate in acidic medium?

1 1

2 2

3 3

4 6

Explanation:

$3 {Sn}^{+ 2} + {Cr}_{2} O_{7}^{- 2} + 14 H^{+} \to$
$3 S n^{+ 4} + 2 C r^{+ 3} + 7 H_{2} O$
So, 1 mole $K_{2} {Cr}_{2} O_{7}$ oxidises 3 moles of ${SnCl}_{2}$ to ${SnCl}_{4}$ .

CHXII08:THE D- & F-BLOCK ELEMENTS

321294 A white crystalline salt A reacts with dilute $HCl$ to liberate a suffocating gas B and also forms a yellow precipitate. The gas $B$ turns potassium dichromate acidified with dilute $H_{2} {SO}_{4}$ to a green coloured solution C. A, B and C are respectively

1

{Na}_{2} {SO}_{3}, {SO}_{2}, {Cr}_{2} {({SO}_{4})}_{3}

2

{Na}_{2} S_{2} O_{3}, {SO}_{2}, {Cr}_{2} {({SO}_{4})}_{3}

3

{Na}_{2} S, {SO}_{2}, {Cr}_{2} {({SO}_{4})}_{3}

4

{Na}_{2} {SO}_{4}, {SO}_{2}, {Cr}_{2} {({SO}_{4})}_{3}

Explanation:

Dil.HCl decomposes ${Na}_{2} S_{2} O_{3} (A)$ with evolution of a gas which possesses a suffocating smell of burning sulphur i.e., ${SO}_{2} (B)$ and yellow ppt. of sulphur is obtained.
$N a_{2} S_{2} O_{3} + 2 H C l \to 2 N a C l + S O_{2} ↑ + S ↓ + H_{2} O$
$(A) (B) (Y e l l o w p p t .)$
When acidified potassium dichromate paper is exposed to the gas, it attains a green colour due to the formation of chromium sulphate.
$K_{2} C r_{2} O_{7} + H_{2} S O_{4} + 3 S O_{2} \to$
$K_{2} S O_{4} + C r_{2} (S O_{4})_{3} + H_{2} O$
$(C)$
$G r e e n$

KCET - 2010

CHXII08:THE D- & F-BLOCK ELEMENTS

321295 The oxidation state of chromium in the final product formed by the reaction between $KI$ and acidified potassium dichromate solution is

1 +3

2 +2

3 +6

4 +4

Explanation:

${Cr}_{2} O_{7}^{2 -} + 14 H^{+} + 6 I^{-} \to 2 {Cr}^{3 +} + 7 H_{2} O + 3 I_{2}$
Thus, oxidation state of $Cr$ in product is +3 .

AIIMS - 2012

CHXII08:THE D- & F-BLOCK ELEMENTS

321296 Yellow compound of lead chromate gets dissolved on treatment with hot $NaOH$ solution. The product of lead formed is a :

1 Tetraanionic complex with coordination number six.

2 Neutral complex with coordination number four.

3 Dianionic complex with coordination number six.

4 Dianionic complex with coordination number four.

Explanation:

Yellow ppt. of ${PbCrO}_{4} ↓$ is soluble in hot $NaOH$ , forming ${[Pb (OH)_{4}]}^{2 -}$ , as ${Pb}^{2 +}$ is amphoteric in nature. ${[Pb (OH)_{4}]}^{2 -}$ is divalent with coordination number 4 .

JEE - 2024

CHXII08:THE D- & F-BLOCK ELEMENTS

321292 Which of the following statement is false?

1

{Na}_{2} {Cr}_{2} O_{7}

is less soluble than

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

2

{CrO}_{7}^{2 -}

has a

Cr - O - Cr

bond.

3

{Na}_{2} {Cr}_{2} O_{7}

is primary standard in volumetry.

4

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

is tetrahedral in shape.

Explanation:

supporting img

${Na}_{2} {Cr}_{2} O_{7}$ is used as primary standard in volumetry. Hydration energy of ${Na}^{\oplus}$ is greater than $K^{\oplus}$ .
Because of smaller size of ${Na}^{\oplus}, {Na}_{2} {Cr}_{2} O_{7}$ is more soluble than $K_{2} {Cr}_{2} O_{7}$ .

JEE - 2015

CHXII08:THE D- & F-BLOCK ELEMENTS

321293 How many moles of stannic chloride can be formed when excess stannous chloride reacts with 1 mole of potassium dichromate in acidic medium?

1 1

2 2

3 3

4 6

Explanation:

$3 {Sn}^{+ 2} + {Cr}_{2} O_{7}^{- 2} + 14 H^{+} \to$
$3 S n^{+ 4} + 2 C r^{+ 3} + 7 H_{2} O$
So, 1 mole $K_{2} {Cr}_{2} O_{7}$ oxidises 3 moles of ${SnCl}_{2}$ to ${SnCl}_{4}$ .

CHXII08:THE D- & F-BLOCK ELEMENTS

321294 A white crystalline salt A reacts with dilute $HCl$ to liberate a suffocating gas B and also forms a yellow precipitate. The gas $B$ turns potassium dichromate acidified with dilute $H_{2} {SO}_{4}$ to a green coloured solution C. A, B and C are respectively

1

{Na}_{2} {SO}_{3}, {SO}_{2}, {Cr}_{2} {({SO}_{4})}_{3}

2

{Na}_{2} S_{2} O_{3}, {SO}_{2}, {Cr}_{2} {({SO}_{4})}_{3}

3

{Na}_{2} S, {SO}_{2}, {Cr}_{2} {({SO}_{4})}_{3}

4

{Na}_{2} {SO}_{4}, {SO}_{2}, {Cr}_{2} {({SO}_{4})}_{3}

Explanation:

Dil.HCl decomposes ${Na}_{2} S_{2} O_{3} (A)$ with evolution of a gas which possesses a suffocating smell of burning sulphur i.e., ${SO}_{2} (B)$ and yellow ppt. of sulphur is obtained.
$N a_{2} S_{2} O_{3} + 2 H C l \to 2 N a C l + S O_{2} ↑ + S ↓ + H_{2} O$
$(A) (B) (Y e l l o w p p t .)$
When acidified potassium dichromate paper is exposed to the gas, it attains a green colour due to the formation of chromium sulphate.
$K_{2} C r_{2} O_{7} + H_{2} S O_{4} + 3 S O_{2} \to$
$K_{2} S O_{4} + C r_{2} (S O_{4})_{3} + H_{2} O$
$(C)$
$G r e e n$

KCET - 2010

CHXII08:THE D- & F-BLOCK ELEMENTS

321295 The oxidation state of chromium in the final product formed by the reaction between $KI$ and acidified potassium dichromate solution is

1 +3

2 +2

3 +6

4 +4

Explanation:

${Cr}_{2} O_{7}^{2 -} + 14 H^{+} + 6 I^{-} \to 2 {Cr}^{3 +} + 7 H_{2} O + 3 I_{2}$
Thus, oxidation state of $Cr$ in product is +3 .

AIIMS - 2012

CHXII08:THE D- & F-BLOCK ELEMENTS

321296 Yellow compound of lead chromate gets dissolved on treatment with hot $NaOH$ solution. The product of lead formed is a :

1 Tetraanionic complex with coordination number six.

2 Neutral complex with coordination number four.

3 Dianionic complex with coordination number six.

4 Dianionic complex with coordination number four.

Explanation:

Yellow ppt. of ${PbCrO}_{4} ↓$ is soluble in hot $NaOH$ , forming ${[Pb (OH)_{4}]}^{2 -}$ , as ${Pb}^{2 +}$ is amphoteric in nature. ${[Pb (OH)_{4}]}^{2 -}$ is divalent with coordination number 4 .

JEE - 2024

CHXII08:THE D- & F-BLOCK ELEMENTS

321292 Which of the following statement is false?

1

{Na}_{2} {Cr}_{2} O_{7}

is less soluble than

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

2

{CrO}_{7}^{2 -}

has a

Cr - O - Cr

bond.

3

{Na}_{2} {Cr}_{2} O_{7}

is primary standard in volumetry.

4

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

is tetrahedral in shape.

Explanation:

supporting img

${Na}_{2} {Cr}_{2} O_{7}$ is used as primary standard in volumetry. Hydration energy of ${Na}^{\oplus}$ is greater than $K^{\oplus}$ .
Because of smaller size of ${Na}^{\oplus}, {Na}_{2} {Cr}_{2} O_{7}$ is more soluble than $K_{2} {Cr}_{2} O_{7}$ .

JEE - 2015

CHXII08:THE D- & F-BLOCK ELEMENTS

321293 How many moles of stannic chloride can be formed when excess stannous chloride reacts with 1 mole of potassium dichromate in acidic medium?

1 1

2 2

3 3

4 6

Explanation:

$3 {Sn}^{+ 2} + {Cr}_{2} O_{7}^{- 2} + 14 H^{+} \to$
$3 S n^{+ 4} + 2 C r^{+ 3} + 7 H_{2} O$
So, 1 mole $K_{2} {Cr}_{2} O_{7}$ oxidises 3 moles of ${SnCl}_{2}$ to ${SnCl}_{4}$ .

CHXII08:THE D- & F-BLOCK ELEMENTS

321294 A white crystalline salt A reacts with dilute $HCl$ to liberate a suffocating gas B and also forms a yellow precipitate. The gas $B$ turns potassium dichromate acidified with dilute $H_{2} {SO}_{4}$ to a green coloured solution C. A, B and C are respectively

1

{Na}_{2} {SO}_{3}, {SO}_{2}, {Cr}_{2} {({SO}_{4})}_{3}

2

{Na}_{2} S_{2} O_{3}, {SO}_{2}, {Cr}_{2} {({SO}_{4})}_{3}

3

{Na}_{2} S, {SO}_{2}, {Cr}_{2} {({SO}_{4})}_{3}

4

{Na}_{2} {SO}_{4}, {SO}_{2}, {Cr}_{2} {({SO}_{4})}_{3}

Explanation:

Dil.HCl decomposes ${Na}_{2} S_{2} O_{3} (A)$ with evolution of a gas which possesses a suffocating smell of burning sulphur i.e., ${SO}_{2} (B)$ and yellow ppt. of sulphur is obtained.
$N a_{2} S_{2} O_{3} + 2 H C l \to 2 N a C l + S O_{2} ↑ + S ↓ + H_{2} O$
$(A) (B) (Y e l l o w p p t .)$
When acidified potassium dichromate paper is exposed to the gas, it attains a green colour due to the formation of chromium sulphate.
$K_{2} C r_{2} O_{7} + H_{2} S O_{4} + 3 S O_{2} \to$
$K_{2} S O_{4} + C r_{2} (S O_{4})_{3} + H_{2} O$
$(C)$
$G r e e n$

KCET - 2010

CHXII08:THE D- & F-BLOCK ELEMENTS

321295 The oxidation state of chromium in the final product formed by the reaction between $KI$ and acidified potassium dichromate solution is

1 +3

2 +2

3 +6

4 +4

Explanation:

${Cr}_{2} O_{7}^{2 -} + 14 H^{+} + 6 I^{-} \to 2 {Cr}^{3 +} + 7 H_{2} O + 3 I_{2}$
Thus, oxidation state of $Cr$ in product is +3 .

AIIMS - 2012

CHXII08:THE D- & F-BLOCK ELEMENTS

321296 Yellow compound of lead chromate gets dissolved on treatment with hot $NaOH$ solution. The product of lead formed is a :

1 Tetraanionic complex with coordination number six.

2 Neutral complex with coordination number four.

3 Dianionic complex with coordination number six.

4 Dianionic complex with coordination number four.

Explanation:

Yellow ppt. of ${PbCrO}_{4} ↓$ is soluble in hot $NaOH$ , forming ${[Pb (OH)_{4}]}^{2 -}$ , as ${Pb}^{2 +}$ is amphoteric in nature. ${[Pb (OH)_{4}]}^{2 -}$ is divalent with coordination number 4 .

JEE - 2024

CHXII08:THE D- & F-BLOCK ELEMENTS

321292 Which of the following statement is false?

1

{Na}_{2} {Cr}_{2} O_{7}

is less soluble than

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

2

{CrO}_{7}^{2 -}

has a

Cr - O - Cr

bond.

3

{Na}_{2} {Cr}_{2} O_{7}

is primary standard in volumetry.

4

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

is tetrahedral in shape.

Explanation:

supporting img

${Na}_{2} {Cr}_{2} O_{7}$ is used as primary standard in volumetry. Hydration energy of ${Na}^{\oplus}$ is greater than $K^{\oplus}$ .
Because of smaller size of ${Na}^{\oplus}, {Na}_{2} {Cr}_{2} O_{7}$ is more soluble than $K_{2} {Cr}_{2} O_{7}$ .

JEE - 2015

CHXII08:THE D- & F-BLOCK ELEMENTS

321293 How many moles of stannic chloride can be formed when excess stannous chloride reacts with 1 mole of potassium dichromate in acidic medium?

1 1

2 2

3 3

4 6

Explanation:

$3 {Sn}^{+ 2} + {Cr}_{2} O_{7}^{- 2} + 14 H^{+} \to$
$3 S n^{+ 4} + 2 C r^{+ 3} + 7 H_{2} O$
So, 1 mole $K_{2} {Cr}_{2} O_{7}$ oxidises 3 moles of ${SnCl}_{2}$ to ${SnCl}_{4}$ .

CHXII08:THE D- & F-BLOCK ELEMENTS

321294 A white crystalline salt A reacts with dilute $HCl$ to liberate a suffocating gas B and also forms a yellow precipitate. The gas $B$ turns potassium dichromate acidified with dilute $H_{2} {SO}_{4}$ to a green coloured solution C. A, B and C are respectively

1

{Na}_{2} {SO}_{3}, {SO}_{2}, {Cr}_{2} {({SO}_{4})}_{3}

2

{Na}_{2} S_{2} O_{3}, {SO}_{2}, {Cr}_{2} {({SO}_{4})}_{3}

3

{Na}_{2} S, {SO}_{2}, {Cr}_{2} {({SO}_{4})}_{3}

4

{Na}_{2} {SO}_{4}, {SO}_{2}, {Cr}_{2} {({SO}_{4})}_{3}

Explanation:

Dil.HCl decomposes ${Na}_{2} S_{2} O_{3} (A)$ with evolution of a gas which possesses a suffocating smell of burning sulphur i.e., ${SO}_{2} (B)$ and yellow ppt. of sulphur is obtained.
$N a_{2} S_{2} O_{3} + 2 H C l \to 2 N a C l + S O_{2} ↑ + S ↓ + H_{2} O$
$(A) (B) (Y e l l o w p p t .)$
When acidified potassium dichromate paper is exposed to the gas, it attains a green colour due to the formation of chromium sulphate.
$K_{2} C r_{2} O_{7} + H_{2} S O_{4} + 3 S O_{2} \to$
$K_{2} S O_{4} + C r_{2} (S O_{4})_{3} + H_{2} O$
$(C)$
$G r e e n$

KCET - 2010

CHXII08:THE D- & F-BLOCK ELEMENTS

321295 The oxidation state of chromium in the final product formed by the reaction between $KI$ and acidified potassium dichromate solution is

1 +3

2 +2

3 +6

4 +4

Explanation:

${Cr}_{2} O_{7}^{2 -} + 14 H^{+} + 6 I^{-} \to 2 {Cr}^{3 +} + 7 H_{2} O + 3 I_{2}$
Thus, oxidation state of $Cr$ in product is +3 .

AIIMS - 2012

CHXII08:THE D- & F-BLOCK ELEMENTS

321296 Yellow compound of lead chromate gets dissolved on treatment with hot $NaOH$ solution. The product of lead formed is a :

1 Tetraanionic complex with coordination number six.

2 Neutral complex with coordination number four.

3 Dianionic complex with coordination number six.

4 Dianionic complex with coordination number four.

Explanation:

Yellow ppt. of ${PbCrO}_{4} ↓$ is soluble in hot $NaOH$ , forming ${[Pb (OH)_{4}]}^{2 -}$ , as ${Pb}^{2 +}$ is amphoteric in nature. ${[Pb (OH)_{4}]}^{2 -}$ is divalent with coordination number 4 .

JEE - 2024