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CHEMISTRY(KCET)

285456 Which of the following pairs has both the ions coloured in aqueous solution?
[Atomic number of $Sc = 21, Ti = 22, Ni = 28, Cu =$ 29, $Mn = 25]$

1

{Sc}^{3 +}, {Mn}^{2 +}

2

{Ni}^{2 +}, {Ti}^{4 +}

3

{Ti}^{3 +}, {Cu}^{+}

4

{Mn}^{2 +}, {Ti}^{3 +}

Explanation:

(d) For an ionic species of transition metals to be coloured, it should show $d - d$ transition.
In order to show $d - d$ transition it must contains unpaired electrons.

Karnataka CET 2021

CHEMISTRY(KCET)

285472 ${Mn}^{2 +}$ compounds are more stable than ${Fe}^{2 +}$ compounds towards oxidation to their +3 state, because

1

{Mn}^{2 +}

is more stable with high

3^{rd}

ionisation energy

2

{Mn}^{2 +}

is bigger in size

3

{Mn}^{2 +}

has completely filled

d

-orbitals

4

{Mn}^{2 +}

does not exist.

Explanation:

(a) ${Mn}^{2 +}$ has stable half-filled electronic configuration thus, it has high third ionisation energy while ${Fe}^{2 +}$ on losing one more electron will acquire this stable electronic configuration. Thus, ${Fe}^{2 +}$ is more prone to get oxidised to +3 oxidation state.
(Y)

Karnataka CET 2016

CHEMISTRY(KCET)

285475 On heating potassium permanganate, one of the following compound is not obtained

1 MnO

2

K_{2} {MnO}_{4}

3

O_{2}

4

{MnO}_{2}

Explanation:

(a) $2 {KMnO}_{4} \overset{Δ}{\to} K_{2} {MnO}_{4} + {MnO}_{2} + O_{2}$

Karnataka CET 2015

CHEMISTRY(KCET)

285457 Aqueous solution of a salt $(A)$ forms a dense white precipitate with ${BaCl}_{2}$ solution. The precipitate dissolves in dilute ${HCl}^{2}$ to produce a gas ( $B$ ) which decolourises acidified ${KMnO}_{4}$ solution. $A$ and $B$ respectively are

1

{BaSO}_{4}, H_{2} S

2

{BaSO}_{3}, H_{2} S

3

{BaSO}_{4}, {SO}_{2}

4

{BaSO}_{3}, {SO}_{2}

Explanation:

(None) ${Na}_{2} {SO}_{3}$ (aq) $+ {BaCl}_{2}$ (aq) $\to$ (A)
$\begin{aligned} {BaSO}_{3} ↓ + 2 NaCl (aq) \\ (Whiteppt) \end{aligned}$
${BaSO}_{3} (s) + 2 HCl (diL) \to {BaCl}_{2} + {SO}_{2} (g) + H_{2} O$
${BaCl}_{2}$ is soluble in water, hence white precepitate disappears.
$5 {SO}_{2} + 2 {MnO}_{4}^{-} + 2 H_{2} O \to 5 {SO}_{4}^{2 -} + 4 H^{+} + 2 {Mn}^{2 +}$
(B) (coloured) (colourless)

Karnataka CET 2020

CHEMISTRY(KCET)

285458 Identify the set of paramagnetic ions among the following:

1

{Ni}^{2 +}, {Cu}^{2 +}, {Zn}^{2 +}

2

{Ti}^{3 +}, {Cu}^{2 +}, {Mn}^{3 +}

3

{Sc}^{3 +}, {Ti}^{3 +}, V^{3 +}

4

V^{2 +}, {Co}^{2 +}, {Ti}^{4 +}

Explanation:

(b) $_{22} Ti \Rightarrow [Ar] 3 d^{2} 4 s^{2}$
${Ti}^{3 +} \Rightarrow [Ar] 3 d^{1} 4 s^{0} \Rightarrow$ paramagnetic due to one unpaired electron.
$\begin{aligned} _{29} Cu \Rightarrow [Ar] 3 d^{10} 4 s^{1} \\ {Cu}^{2 +} \Rightarrow [Ar] 3 d^{9} 4 s^{0} \end{aligned}$
Paramagnetic due to one unpaired electron.
$_{25} Mn \Rightarrow [Ar] 3 d^{5} 4 s^{2}$
${Mn}^{3 +} \Rightarrow [Ar] 3 d^{4} 4 s^{0}$
Paramagnetic due to four unpaired electrons.

Karnataka CET 2020

CHEMISTRY(KCET)

285456 Which of the following pairs has both the ions coloured in aqueous solution?
[Atomic number of $Sc = 21, Ti = 22, Ni = 28, Cu =$ 29, $Mn = 25]$

1

{Sc}^{3 +}, {Mn}^{2 +}

2

{Ni}^{2 +}, {Ti}^{4 +}

3

{Ti}^{3 +}, {Cu}^{+}

4

{Mn}^{2 +}, {Ti}^{3 +}

Explanation:

(d) For an ionic species of transition metals to be coloured, it should show $d - d$ transition.
In order to show $d - d$ transition it must contains unpaired electrons.

Karnataka CET 2021

CHEMISTRY(KCET)

285472 ${Mn}^{2 +}$ compounds are more stable than ${Fe}^{2 +}$ compounds towards oxidation to their +3 state, because

1

{Mn}^{2 +}

is more stable with high

3^{rd}

ionisation energy

2

{Mn}^{2 +}

is bigger in size

3

{Mn}^{2 +}

has completely filled

d

-orbitals

4

{Mn}^{2 +}

does not exist.

Explanation:

(a) ${Mn}^{2 +}$ has stable half-filled electronic configuration thus, it has high third ionisation energy while ${Fe}^{2 +}$ on losing one more electron will acquire this stable electronic configuration. Thus, ${Fe}^{2 +}$ is more prone to get oxidised to +3 oxidation state.
(Y)

Karnataka CET 2016

CHEMISTRY(KCET)

285475 On heating potassium permanganate, one of the following compound is not obtained

1 MnO

2

K_{2} {MnO}_{4}

3

O_{2}

4

{MnO}_{2}

Explanation:

(a) $2 {KMnO}_{4} \overset{Δ}{\to} K_{2} {MnO}_{4} + {MnO}_{2} + O_{2}$

Karnataka CET 2015

CHEMISTRY(KCET)

285457 Aqueous solution of a salt $(A)$ forms a dense white precipitate with ${BaCl}_{2}$ solution. The precipitate dissolves in dilute ${HCl}^{2}$ to produce a gas ( $B$ ) which decolourises acidified ${KMnO}_{4}$ solution. $A$ and $B$ respectively are

1

{BaSO}_{4}, H_{2} S

2

{BaSO}_{3}, H_{2} S

3

{BaSO}_{4}, {SO}_{2}

4

{BaSO}_{3}, {SO}_{2}

Explanation:

(None) ${Na}_{2} {SO}_{3}$ (aq) $+ {BaCl}_{2}$ (aq) $\to$ (A)
$\begin{aligned} {BaSO}_{3} ↓ + 2 NaCl (aq) \\ (Whiteppt) \end{aligned}$
${BaSO}_{3} (s) + 2 HCl (diL) \to {BaCl}_{2} + {SO}_{2} (g) + H_{2} O$
${BaCl}_{2}$ is soluble in water, hence white precepitate disappears.
$5 {SO}_{2} + 2 {MnO}_{4}^{-} + 2 H_{2} O \to 5 {SO}_{4}^{2 -} + 4 H^{+} + 2 {Mn}^{2 +}$
(B) (coloured) (colourless)

Karnataka CET 2020

CHEMISTRY(KCET)

285458 Identify the set of paramagnetic ions among the following:

1

{Ni}^{2 +}, {Cu}^{2 +}, {Zn}^{2 +}

2

{Ti}^{3 +}, {Cu}^{2 +}, {Mn}^{3 +}

3

{Sc}^{3 +}, {Ti}^{3 +}, V^{3 +}

4

V^{2 +}, {Co}^{2 +}, {Ti}^{4 +}

Explanation:

(b) $_{22} Ti \Rightarrow [Ar] 3 d^{2} 4 s^{2}$
${Ti}^{3 +} \Rightarrow [Ar] 3 d^{1} 4 s^{0} \Rightarrow$ paramagnetic due to one unpaired electron.
$\begin{aligned} _{29} Cu \Rightarrow [Ar] 3 d^{10} 4 s^{1} \\ {Cu}^{2 +} \Rightarrow [Ar] 3 d^{9} 4 s^{0} \end{aligned}$
Paramagnetic due to one unpaired electron.
$_{25} Mn \Rightarrow [Ar] 3 d^{5} 4 s^{2}$
${Mn}^{3 +} \Rightarrow [Ar] 3 d^{4} 4 s^{0}$
Paramagnetic due to four unpaired electrons.

Karnataka CET 2020

CHEMISTRY(KCET)

285456 Which of the following pairs has both the ions coloured in aqueous solution?
[Atomic number of $Sc = 21, Ti = 22, Ni = 28, Cu =$ 29, $Mn = 25]$

1

{Sc}^{3 +}, {Mn}^{2 +}

2

{Ni}^{2 +}, {Ti}^{4 +}

3

{Ti}^{3 +}, {Cu}^{+}

4

{Mn}^{2 +}, {Ti}^{3 +}

Explanation:

(d) For an ionic species of transition metals to be coloured, it should show $d - d$ transition.
In order to show $d - d$ transition it must contains unpaired electrons.

Karnataka CET 2021

CHEMISTRY(KCET)

285472 ${Mn}^{2 +}$ compounds are more stable than ${Fe}^{2 +}$ compounds towards oxidation to their +3 state, because

1

{Mn}^{2 +}

is more stable with high

3^{rd}

ionisation energy

2

{Mn}^{2 +}

is bigger in size

3

{Mn}^{2 +}

has completely filled

d

-orbitals

4

{Mn}^{2 +}

does not exist.

Explanation:

(a) ${Mn}^{2 +}$ has stable half-filled electronic configuration thus, it has high third ionisation energy while ${Fe}^{2 +}$ on losing one more electron will acquire this stable electronic configuration. Thus, ${Fe}^{2 +}$ is more prone to get oxidised to +3 oxidation state.
(Y)

Karnataka CET 2016

CHEMISTRY(KCET)

285475 On heating potassium permanganate, one of the following compound is not obtained

1 MnO

2

K_{2} {MnO}_{4}

3

O_{2}

4

{MnO}_{2}

Explanation:

(a) $2 {KMnO}_{4} \overset{Δ}{\to} K_{2} {MnO}_{4} + {MnO}_{2} + O_{2}$

Karnataka CET 2015

CHEMISTRY(KCET)

285457 Aqueous solution of a salt $(A)$ forms a dense white precipitate with ${BaCl}_{2}$ solution. The precipitate dissolves in dilute ${HCl}^{2}$ to produce a gas ( $B$ ) which decolourises acidified ${KMnO}_{4}$ solution. $A$ and $B$ respectively are

1

{BaSO}_{4}, H_{2} S

2

{BaSO}_{3}, H_{2} S

3

{BaSO}_{4}, {SO}_{2}

4

{BaSO}_{3}, {SO}_{2}

Explanation:

(None) ${Na}_{2} {SO}_{3}$ (aq) $+ {BaCl}_{2}$ (aq) $\to$ (A)
$\begin{aligned} {BaSO}_{3} ↓ + 2 NaCl (aq) \\ (Whiteppt) \end{aligned}$
${BaSO}_{3} (s) + 2 HCl (diL) \to {BaCl}_{2} + {SO}_{2} (g) + H_{2} O$
${BaCl}_{2}$ is soluble in water, hence white precepitate disappears.
$5 {SO}_{2} + 2 {MnO}_{4}^{-} + 2 H_{2} O \to 5 {SO}_{4}^{2 -} + 4 H^{+} + 2 {Mn}^{2 +}$
(B) (coloured) (colourless)

Karnataka CET 2020

CHEMISTRY(KCET)

285458 Identify the set of paramagnetic ions among the following:

1

{Ni}^{2 +}, {Cu}^{2 +}, {Zn}^{2 +}

2

{Ti}^{3 +}, {Cu}^{2 +}, {Mn}^{3 +}

3

{Sc}^{3 +}, {Ti}^{3 +}, V^{3 +}

4

V^{2 +}, {Co}^{2 +}, {Ti}^{4 +}

Explanation:

(b) $_{22} Ti \Rightarrow [Ar] 3 d^{2} 4 s^{2}$
${Ti}^{3 +} \Rightarrow [Ar] 3 d^{1} 4 s^{0} \Rightarrow$ paramagnetic due to one unpaired electron.
$\begin{aligned} _{29} Cu \Rightarrow [Ar] 3 d^{10} 4 s^{1} \\ {Cu}^{2 +} \Rightarrow [Ar] 3 d^{9} 4 s^{0} \end{aligned}$
Paramagnetic due to one unpaired electron.
$_{25} Mn \Rightarrow [Ar] 3 d^{5} 4 s^{2}$
${Mn}^{3 +} \Rightarrow [Ar] 3 d^{4} 4 s^{0}$
Paramagnetic due to four unpaired electrons.

Karnataka CET 2020

CHEMISTRY(KCET)

285456 Which of the following pairs has both the ions coloured in aqueous solution?
[Atomic number of $Sc = 21, Ti = 22, Ni = 28, Cu =$ 29, $Mn = 25]$

1

{Sc}^{3 +}, {Mn}^{2 +}

2

{Ni}^{2 +}, {Ti}^{4 +}

3

{Ti}^{3 +}, {Cu}^{+}

4

{Mn}^{2 +}, {Ti}^{3 +}

Explanation:

(d) For an ionic species of transition metals to be coloured, it should show $d - d$ transition.
In order to show $d - d$ transition it must contains unpaired electrons.

Karnataka CET 2021

CHEMISTRY(KCET)

285472 ${Mn}^{2 +}$ compounds are more stable than ${Fe}^{2 +}$ compounds towards oxidation to their +3 state, because

1

{Mn}^{2 +}

is more stable with high

3^{rd}

ionisation energy

2

{Mn}^{2 +}

is bigger in size

3

{Mn}^{2 +}

has completely filled

d

-orbitals

4

{Mn}^{2 +}

does not exist.

Explanation:

(a) ${Mn}^{2 +}$ has stable half-filled electronic configuration thus, it has high third ionisation energy while ${Fe}^{2 +}$ on losing one more electron will acquire this stable electronic configuration. Thus, ${Fe}^{2 +}$ is more prone to get oxidised to +3 oxidation state.
(Y)

Karnataka CET 2016

CHEMISTRY(KCET)

285475 On heating potassium permanganate, one of the following compound is not obtained

1 MnO

2

K_{2} {MnO}_{4}

3

O_{2}

4

{MnO}_{2}

Explanation:

(a) $2 {KMnO}_{4} \overset{Δ}{\to} K_{2} {MnO}_{4} + {MnO}_{2} + O_{2}$

Karnataka CET 2015

CHEMISTRY(KCET)

285457 Aqueous solution of a salt $(A)$ forms a dense white precipitate with ${BaCl}_{2}$ solution. The precipitate dissolves in dilute ${HCl}^{2}$ to produce a gas ( $B$ ) which decolourises acidified ${KMnO}_{4}$ solution. $A$ and $B$ respectively are

1

{BaSO}_{4}, H_{2} S

2

{BaSO}_{3}, H_{2} S

3

{BaSO}_{4}, {SO}_{2}

4

{BaSO}_{3}, {SO}_{2}

Explanation:

(None) ${Na}_{2} {SO}_{3}$ (aq) $+ {BaCl}_{2}$ (aq) $\to$ (A)
$\begin{aligned} {BaSO}_{3} ↓ + 2 NaCl (aq) \\ (Whiteppt) \end{aligned}$
${BaSO}_{3} (s) + 2 HCl (diL) \to {BaCl}_{2} + {SO}_{2} (g) + H_{2} O$
${BaCl}_{2}$ is soluble in water, hence white precepitate disappears.
$5 {SO}_{2} + 2 {MnO}_{4}^{-} + 2 H_{2} O \to 5 {SO}_{4}^{2 -} + 4 H^{+} + 2 {Mn}^{2 +}$
(B) (coloured) (colourless)

Karnataka CET 2020

CHEMISTRY(KCET)

285458 Identify the set of paramagnetic ions among the following:

1

{Ni}^{2 +}, {Cu}^{2 +}, {Zn}^{2 +}

2

{Ti}^{3 +}, {Cu}^{2 +}, {Mn}^{3 +}

3

{Sc}^{3 +}, {Ti}^{3 +}, V^{3 +}

4

V^{2 +}, {Co}^{2 +}, {Ti}^{4 +}

Explanation:

(b) $_{22} Ti \Rightarrow [Ar] 3 d^{2} 4 s^{2}$
${Ti}^{3 +} \Rightarrow [Ar] 3 d^{1} 4 s^{0} \Rightarrow$ paramagnetic due to one unpaired electron.
$\begin{aligned} _{29} Cu \Rightarrow [Ar] 3 d^{10} 4 s^{1} \\ {Cu}^{2 +} \Rightarrow [Ar] 3 d^{9} 4 s^{0} \end{aligned}$
Paramagnetic due to one unpaired electron.
$_{25} Mn \Rightarrow [Ar] 3 d^{5} 4 s^{2}$
${Mn}^{3 +} \Rightarrow [Ar] 3 d^{4} 4 s^{0}$
Paramagnetic due to four unpaired electrons.

Karnataka CET 2020

CHEMISTRY(KCET)

285456 Which of the following pairs has both the ions coloured in aqueous solution?
[Atomic number of $Sc = 21, Ti = 22, Ni = 28, Cu =$ 29, $Mn = 25]$

1

{Sc}^{3 +}, {Mn}^{2 +}

2

{Ni}^{2 +}, {Ti}^{4 +}

3

{Ti}^{3 +}, {Cu}^{+}

4

{Mn}^{2 +}, {Ti}^{3 +}

Explanation:

(d) For an ionic species of transition metals to be coloured, it should show $d - d$ transition.
In order to show $d - d$ transition it must contains unpaired electrons.

Karnataka CET 2021

CHEMISTRY(KCET)

285472 ${Mn}^{2 +}$ compounds are more stable than ${Fe}^{2 +}$ compounds towards oxidation to their +3 state, because

1

{Mn}^{2 +}

is more stable with high

3^{rd}

ionisation energy

2

{Mn}^{2 +}

is bigger in size

3

{Mn}^{2 +}

has completely filled

d

-orbitals

4

{Mn}^{2 +}

does not exist.

Explanation:

(a) ${Mn}^{2 +}$ has stable half-filled electronic configuration thus, it has high third ionisation energy while ${Fe}^{2 +}$ on losing one more electron will acquire this stable electronic configuration. Thus, ${Fe}^{2 +}$ is more prone to get oxidised to +3 oxidation state.
(Y)

Karnataka CET 2016

CHEMISTRY(KCET)

285475 On heating potassium permanganate, one of the following compound is not obtained

1 MnO

2

K_{2} {MnO}_{4}

3

O_{2}

4

{MnO}_{2}

Explanation:

(a) $2 {KMnO}_{4} \overset{Δ}{\to} K_{2} {MnO}_{4} + {MnO}_{2} + O_{2}$

Karnataka CET 2015

CHEMISTRY(KCET)

285457 Aqueous solution of a salt $(A)$ forms a dense white precipitate with ${BaCl}_{2}$ solution. The precipitate dissolves in dilute ${HCl}^{2}$ to produce a gas ( $B$ ) which decolourises acidified ${KMnO}_{4}$ solution. $A$ and $B$ respectively are

1

{BaSO}_{4}, H_{2} S

2

{BaSO}_{3}, H_{2} S

3

{BaSO}_{4}, {SO}_{2}

4

{BaSO}_{3}, {SO}_{2}

Explanation:

(None) ${Na}_{2} {SO}_{3}$ (aq) $+ {BaCl}_{2}$ (aq) $\to$ (A)
$\begin{aligned} {BaSO}_{3} ↓ + 2 NaCl (aq) \\ (Whiteppt) \end{aligned}$
${BaSO}_{3} (s) + 2 HCl (diL) \to {BaCl}_{2} + {SO}_{2} (g) + H_{2} O$
${BaCl}_{2}$ is soluble in water, hence white precepitate disappears.
$5 {SO}_{2} + 2 {MnO}_{4}^{-} + 2 H_{2} O \to 5 {SO}_{4}^{2 -} + 4 H^{+} + 2 {Mn}^{2 +}$
(B) (coloured) (colourless)

Karnataka CET 2020

CHEMISTRY(KCET)

285458 Identify the set of paramagnetic ions among the following:

1

{Ni}^{2 +}, {Cu}^{2 +}, {Zn}^{2 +}

2

{Ti}^{3 +}, {Cu}^{2 +}, {Mn}^{3 +}

3

{Sc}^{3 +}, {Ti}^{3 +}, V^{3 +}

4

V^{2 +}, {Co}^{2 +}, {Ti}^{4 +}

Explanation:

(b) $_{22} Ti \Rightarrow [Ar] 3 d^{2} 4 s^{2}$
${Ti}^{3 +} \Rightarrow [Ar] 3 d^{1} 4 s^{0} \Rightarrow$ paramagnetic due to one unpaired electron.
$\begin{aligned} _{29} Cu \Rightarrow [Ar] 3 d^{10} 4 s^{1} \\ {Cu}^{2 +} \Rightarrow [Ar] 3 d^{9} 4 s^{0} \end{aligned}$
Paramagnetic due to one unpaired electron.
$_{25} Mn \Rightarrow [Ar] 3 d^{5} 4 s^{2}$
${Mn}^{3 +} \Rightarrow [Ar] 3 d^{4} 4 s^{0}$
Paramagnetic due to four unpaired electrons.

Karnataka CET 2020