QBManager

CHXII08:THE D- & F-BLOCK ELEMENTS

321219 An aqueous solution of ${CoCl}_{2}$ on addition of excess of conc. $HCl$ turns blue due to the formation of

1

[Co (H_{2} O)] {Cl}_{2}

2

{[Co {(H_{2} O)}_{2} {Cl}_{4}]}^{2 -}

3

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

4

[Co {(H_{2} O)}_{2} {Cl}_{2}]

Explanation:

${CoCl}_{2}$ , a weak Lewis acid, reacts with chloride ion to produce salt containing the tetrahedral ${[{CoCl}_{4}]}^{2 -}$ ion. It is blue when anhydrous and a deep magenta colour when hydrated, and for this reason it is widely used as an indicator in water.

CHXII08:THE D- & F-BLOCK ELEMENTS

321220 Which of the following is obtained when auric chloride reacts with sodium chloride?

1

Na [AuCl]

2

Na [{AuCl}_{2}]

3

Na [{AuCl}_{3}]

4

Na [{AuCl}_{4}]

Explanation:

$\begin{array}{l} A u C l_{3} + N a C l \to N a [A u C l_{4}] \\ S o d i u m \\ c h l o r o a u r a t e \end{array}$

CHXII08:THE D- & F-BLOCK ELEMENTS

321221 Assertion :
${FeSO}_{4} \cdot 7 H_{2} O$ is a green crystalline compound.
Reason :
Due to atmospheric oxidation, these crystals acquire brown yellow colour.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

Explanation:

$\underset{(green)}{4 FeS O_{4}} + 2 H_{2} O + O_{2} \to \underset{\underset{(brownish yellow)}{Basic ferric sulphate}}{4 Fe (OH) . S O_{4}}$
Light green crystals of ferrous sulphate lose water molecule and turn brown on exposure to air. This is due to its oxidation to basic ferric sulphate. Both statements are true but not actual reason for the assertion. So option (2) is correct.

CHXII08:THE D- & F-BLOCK ELEMENTS

321222 Assertion :
Aqueous solution of ${FeCl}_{3}$ is acidic.
Reason :
The hydrated form of ${FeCl}_{3}$ consists
of six water molecules, ${FeCl}_{3} \cdot 6 H_{2} O$ .

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

Explanation:

${FeCl}_{3}$ in water shows acidic nature because of cationic hydrolysis of ${Fe}^{3 +}$ .
${FeCl}_{3} + 3 H_{2} O \to Fe (OH)_{3} + 3 HCl$
Given reason is also correct, but it is not the correct explanation of the assertion. So option (2) is correct.

CHXII08:THE D- & F-BLOCK ELEMENTS

321223 Assertion :
A solution of ferric chloride on standing gives a brown precipitate.
Reason :
${FeCl}_{3}$ possesses covalent bonds and chlorine bridge structure.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

Explanation:

Hydrated solution of ${FeCl}_{3}$ gets converted into brown ${Fe}_{2} O_{3}$ due to hydrolysis.
$\begin{aligned} {FeCl}_{3} + 3 H_{2} O \to \underset{Brown ppt}{Fe (OH)_{3}} + 3 HCl \\ Fe (OH)_{3} \to {Fe}_{2} O_{3} + 3 H_{2} O . \end{aligned}$
${FeCl}_{3}$ structure is
supporting img
So option (2) is correct.

CHXII08:THE D- & F-BLOCK ELEMENTS

321219 An aqueous solution of ${CoCl}_{2}$ on addition of excess of conc. $HCl$ turns blue due to the formation of

1

[Co (H_{2} O)] {Cl}_{2}

2

{[Co {(H_{2} O)}_{2} {Cl}_{4}]}^{2 -}

3

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

4

[Co {(H_{2} O)}_{2} {Cl}_{2}]

Explanation:

${CoCl}_{2}$ , a weak Lewis acid, reacts with chloride ion to produce salt containing the tetrahedral ${[{CoCl}_{4}]}^{2 -}$ ion. It is blue when anhydrous and a deep magenta colour when hydrated, and for this reason it is widely used as an indicator in water.

CHXII08:THE D- & F-BLOCK ELEMENTS

321220 Which of the following is obtained when auric chloride reacts with sodium chloride?

1

Na [AuCl]

2

Na [{AuCl}_{2}]

3

Na [{AuCl}_{3}]

4

Na [{AuCl}_{4}]

Explanation:

$\begin{array}{l} A u C l_{3} + N a C l \to N a [A u C l_{4}] \\ S o d i u m \\ c h l o r o a u r a t e \end{array}$

CHXII08:THE D- & F-BLOCK ELEMENTS

321221 Assertion :
${FeSO}_{4} \cdot 7 H_{2} O$ is a green crystalline compound.
Reason :
Due to atmospheric oxidation, these crystals acquire brown yellow colour.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

Explanation:

$\underset{(green)}{4 FeS O_{4}} + 2 H_{2} O + O_{2} \to \underset{\underset{(brownish yellow)}{Basic ferric sulphate}}{4 Fe (OH) . S O_{4}}$
Light green crystals of ferrous sulphate lose water molecule and turn brown on exposure to air. This is due to its oxidation to basic ferric sulphate. Both statements are true but not actual reason for the assertion. So option (2) is correct.

CHXII08:THE D- & F-BLOCK ELEMENTS

321222 Assertion :
Aqueous solution of ${FeCl}_{3}$ is acidic.
Reason :
The hydrated form of ${FeCl}_{3}$ consists
of six water molecules, ${FeCl}_{3} \cdot 6 H_{2} O$ .

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

Explanation:

${FeCl}_{3}$ in water shows acidic nature because of cationic hydrolysis of ${Fe}^{3 +}$ .
${FeCl}_{3} + 3 H_{2} O \to Fe (OH)_{3} + 3 HCl$
Given reason is also correct, but it is not the correct explanation of the assertion. So option (2) is correct.

CHXII08:THE D- & F-BLOCK ELEMENTS

321223 Assertion :
A solution of ferric chloride on standing gives a brown precipitate.
Reason :
${FeCl}_{3}$ possesses covalent bonds and chlorine bridge structure.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

Explanation:

Hydrated solution of ${FeCl}_{3}$ gets converted into brown ${Fe}_{2} O_{3}$ due to hydrolysis.
$\begin{aligned} {FeCl}_{3} + 3 H_{2} O \to \underset{Brown ppt}{Fe (OH)_{3}} + 3 HCl \\ Fe (OH)_{3} \to {Fe}_{2} O_{3} + 3 H_{2} O . \end{aligned}$
${FeCl}_{3}$ structure is
supporting img
So option (2) is correct.

CHXII08:THE D- & F-BLOCK ELEMENTS

321219 An aqueous solution of ${CoCl}_{2}$ on addition of excess of conc. $HCl$ turns blue due to the formation of

1

[Co (H_{2} O)] {Cl}_{2}

2

{[Co {(H_{2} O)}_{2} {Cl}_{4}]}^{2 -}

3

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

4

[Co {(H_{2} O)}_{2} {Cl}_{2}]

Explanation:

${CoCl}_{2}$ , a weak Lewis acid, reacts with chloride ion to produce salt containing the tetrahedral ${[{CoCl}_{4}]}^{2 -}$ ion. It is blue when anhydrous and a deep magenta colour when hydrated, and for this reason it is widely used as an indicator in water.

CHXII08:THE D- & F-BLOCK ELEMENTS

321220 Which of the following is obtained when auric chloride reacts with sodium chloride?

1

Na [AuCl]

2

Na [{AuCl}_{2}]

3

Na [{AuCl}_{3}]

4

Na [{AuCl}_{4}]

Explanation:

$\begin{array}{l} A u C l_{3} + N a C l \to N a [A u C l_{4}] \\ S o d i u m \\ c h l o r o a u r a t e \end{array}$

CHXII08:THE D- & F-BLOCK ELEMENTS

321221 Assertion :
${FeSO}_{4} \cdot 7 H_{2} O$ is a green crystalline compound.
Reason :
Due to atmospheric oxidation, these crystals acquire brown yellow colour.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

Explanation:

$\underset{(green)}{4 FeS O_{4}} + 2 H_{2} O + O_{2} \to \underset{\underset{(brownish yellow)}{Basic ferric sulphate}}{4 Fe (OH) . S O_{4}}$
Light green crystals of ferrous sulphate lose water molecule and turn brown on exposure to air. This is due to its oxidation to basic ferric sulphate. Both statements are true but not actual reason for the assertion. So option (2) is correct.

CHXII08:THE D- & F-BLOCK ELEMENTS

321222 Assertion :
Aqueous solution of ${FeCl}_{3}$ is acidic.
Reason :
The hydrated form of ${FeCl}_{3}$ consists
of six water molecules, ${FeCl}_{3} \cdot 6 H_{2} O$ .

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

Explanation:

${FeCl}_{3}$ in water shows acidic nature because of cationic hydrolysis of ${Fe}^{3 +}$ .
${FeCl}_{3} + 3 H_{2} O \to Fe (OH)_{3} + 3 HCl$
Given reason is also correct, but it is not the correct explanation of the assertion. So option (2) is correct.

CHXII08:THE D- & F-BLOCK ELEMENTS

321223 Assertion :
A solution of ferric chloride on standing gives a brown precipitate.
Reason :
${FeCl}_{3}$ possesses covalent bonds and chlorine bridge structure.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

Explanation:

Hydrated solution of ${FeCl}_{3}$ gets converted into brown ${Fe}_{2} O_{3}$ due to hydrolysis.
$\begin{aligned} {FeCl}_{3} + 3 H_{2} O \to \underset{Brown ppt}{Fe (OH)_{3}} + 3 HCl \\ Fe (OH)_{3} \to {Fe}_{2} O_{3} + 3 H_{2} O . \end{aligned}$
${FeCl}_{3}$ structure is
supporting img
So option (2) is correct.

CHXII08:THE D- & F-BLOCK ELEMENTS

321219 An aqueous solution of ${CoCl}_{2}$ on addition of excess of conc. $HCl$ turns blue due to the formation of

1

[Co (H_{2} O)] {Cl}_{2}

2

{[Co {(H_{2} O)}_{2} {Cl}_{4}]}^{2 -}

3

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

4

[Co {(H_{2} O)}_{2} {Cl}_{2}]

Explanation:

${CoCl}_{2}$ , a weak Lewis acid, reacts with chloride ion to produce salt containing the tetrahedral ${[{CoCl}_{4}]}^{2 -}$ ion. It is blue when anhydrous and a deep magenta colour when hydrated, and for this reason it is widely used as an indicator in water.

CHXII08:THE D- & F-BLOCK ELEMENTS

321220 Which of the following is obtained when auric chloride reacts with sodium chloride?

1

Na [AuCl]

2

Na [{AuCl}_{2}]

3

Na [{AuCl}_{3}]

4

Na [{AuCl}_{4}]

Explanation:

$\begin{array}{l} A u C l_{3} + N a C l \to N a [A u C l_{4}] \\ S o d i u m \\ c h l o r o a u r a t e \end{array}$

CHXII08:THE D- & F-BLOCK ELEMENTS

321221 Assertion :
${FeSO}_{4} \cdot 7 H_{2} O$ is a green crystalline compound.
Reason :
Due to atmospheric oxidation, these crystals acquire brown yellow colour.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

Explanation:

$\underset{(green)}{4 FeS O_{4}} + 2 H_{2} O + O_{2} \to \underset{\underset{(brownish yellow)}{Basic ferric sulphate}}{4 Fe (OH) . S O_{4}}$
Light green crystals of ferrous sulphate lose water molecule and turn brown on exposure to air. This is due to its oxidation to basic ferric sulphate. Both statements are true but not actual reason for the assertion. So option (2) is correct.

CHXII08:THE D- & F-BLOCK ELEMENTS

321222 Assertion :
Aqueous solution of ${FeCl}_{3}$ is acidic.
Reason :
The hydrated form of ${FeCl}_{3}$ consists
of six water molecules, ${FeCl}_{3} \cdot 6 H_{2} O$ .

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

Explanation:

${FeCl}_{3}$ in water shows acidic nature because of cationic hydrolysis of ${Fe}^{3 +}$ .
${FeCl}_{3} + 3 H_{2} O \to Fe (OH)_{3} + 3 HCl$
Given reason is also correct, but it is not the correct explanation of the assertion. So option (2) is correct.

CHXII08:THE D- & F-BLOCK ELEMENTS

321223 Assertion :
A solution of ferric chloride on standing gives a brown precipitate.
Reason :
${FeCl}_{3}$ possesses covalent bonds and chlorine bridge structure.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

Explanation:

Hydrated solution of ${FeCl}_{3}$ gets converted into brown ${Fe}_{2} O_{3}$ due to hydrolysis.
$\begin{aligned} {FeCl}_{3} + 3 H_{2} O \to \underset{Brown ppt}{Fe (OH)_{3}} + 3 HCl \\ Fe (OH)_{3} \to {Fe}_{2} O_{3} + 3 H_{2} O . \end{aligned}$
${FeCl}_{3}$ structure is
supporting img
So option (2) is correct.

CHXII08:THE D- & F-BLOCK ELEMENTS

321219 An aqueous solution of ${CoCl}_{2}$ on addition of excess of conc. $HCl$ turns blue due to the formation of

1

[Co (H_{2} O)] {Cl}_{2}

2

{[Co {(H_{2} O)}_{2} {Cl}_{4}]}^{2 -}

3

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

4

[Co {(H_{2} O)}_{2} {Cl}_{2}]

Explanation:

${CoCl}_{2}$ , a weak Lewis acid, reacts with chloride ion to produce salt containing the tetrahedral ${[{CoCl}_{4}]}^{2 -}$ ion. It is blue when anhydrous and a deep magenta colour when hydrated, and for this reason it is widely used as an indicator in water.

CHXII08:THE D- & F-BLOCK ELEMENTS

321220 Which of the following is obtained when auric chloride reacts with sodium chloride?

1

Na [AuCl]

2

Na [{AuCl}_{2}]

3

Na [{AuCl}_{3}]

4

Na [{AuCl}_{4}]

Explanation:

$\begin{array}{l} A u C l_{3} + N a C l \to N a [A u C l_{4}] \\ S o d i u m \\ c h l o r o a u r a t e \end{array}$

CHXII08:THE D- & F-BLOCK ELEMENTS

321221 Assertion :
${FeSO}_{4} \cdot 7 H_{2} O$ is a green crystalline compound.
Reason :
Due to atmospheric oxidation, these crystals acquire brown yellow colour.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

Explanation:

$\underset{(green)}{4 FeS O_{4}} + 2 H_{2} O + O_{2} \to \underset{\underset{(brownish yellow)}{Basic ferric sulphate}}{4 Fe (OH) . S O_{4}}$
Light green crystals of ferrous sulphate lose water molecule and turn brown on exposure to air. This is due to its oxidation to basic ferric sulphate. Both statements are true but not actual reason for the assertion. So option (2) is correct.

CHXII08:THE D- & F-BLOCK ELEMENTS

321222 Assertion :
Aqueous solution of ${FeCl}_{3}$ is acidic.
Reason :
The hydrated form of ${FeCl}_{3}$ consists
of six water molecules, ${FeCl}_{3} \cdot 6 H_{2} O$ .

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

Explanation:

${FeCl}_{3}$ in water shows acidic nature because of cationic hydrolysis of ${Fe}^{3 +}$ .
${FeCl}_{3} + 3 H_{2} O \to Fe (OH)_{3} + 3 HCl$
Given reason is also correct, but it is not the correct explanation of the assertion. So option (2) is correct.

CHXII08:THE D- & F-BLOCK ELEMENTS

321223 Assertion :
A solution of ferric chloride on standing gives a brown precipitate.
Reason :
${FeCl}_{3}$ possesses covalent bonds and chlorine bridge structure.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

Explanation:

Hydrated solution of ${FeCl}_{3}$ gets converted into brown ${Fe}_{2} O_{3}$ due to hydrolysis.
$\begin{aligned} {FeCl}_{3} + 3 H_{2} O \to \underset{Brown ppt}{Fe (OH)_{3}} + 3 HCl \\ Fe (OH)_{3} \to {Fe}_{2} O_{3} + 3 H_{2} O . \end{aligned}$
${FeCl}_{3}$ structure is
supporting img
So option (2) is correct.

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