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CHXI10:THE S-BLOCK ELEMENTS

315915 Which of the following alkali metal carbonate is least stable and decomposes readily?

1

{LiHCO}_{3}

2

{CaCO}_{3}

3

K_{2} {CO}_{3}

4

{Na}_{2} {CO}_{3}

CHXI10:THE S-BLOCK ELEMENTS

315909 A sodium salt of an unknown anion when treated with ${MgCl}_{2}$ gives white precipitate only on boiling. The anion is

1

{SO}_{4}^{2 -}

2

{HCO}_{3}^{-}

3

{CO}_{3}^{2 -}

4

{NO}_{3}^{-}

Explanation:

$Mg {({HCO}_{3})}_{2}$ on boiling decomposes to give white precipitate of ${MgCO}_{3}$ .
$Mg {({HCO}_{3})}_{2} (aq) \overset{Heat}{⟶} {MgCO}_{3} ↓ + H_{2} O + {CO}_{2} ↑ .$

CHXI10:THE S-BLOCK ELEMENTS

315910 Which does not exists in solid state?

1

{LiHCO}_{3}

2

{CaCO}_{3}

3

{NaHCO}_{3}

4

{Na}_{2} {CO}_{3}

CHXI10:THE S-BLOCK ELEMENTS

315911 Which of the following disproportionate on heating?

1

{Na}_{2} O

2

{Na}_{2} O_{2}

3

BaO

4

{Li}_{2} O

Explanation:

$2 {Na}_{2} O \overset{400^{\circ} C}{⟶} {Na}_{2} O_{2} + 2 Na$ .

CHXI10:THE S-BLOCK ELEMENTS

315912 Among the following, the one that gives pink violet colour to the Bunsen flame is

1

NaCl

2

{BaCl}_{2}

3

CsCl

4

KCl

Explanation:

Potassium salts (i.e. $KCl$ ) impart pinkviolet colour the flame.

CHXI10:THE S-BLOCK ELEMENTS

315915 Which of the following alkali metal carbonate is least stable and decomposes readily?

1

{LiHCO}_{3}

2

{CaCO}_{3}

3

K_{2} {CO}_{3}

4

{Na}_{2} {CO}_{3}

CHXI10:THE S-BLOCK ELEMENTS

315909 A sodium salt of an unknown anion when treated with ${MgCl}_{2}$ gives white precipitate only on boiling. The anion is

1

{SO}_{4}^{2 -}

2

{HCO}_{3}^{-}

3

{CO}_{3}^{2 -}

4

{NO}_{3}^{-}

Explanation:

$Mg {({HCO}_{3})}_{2}$ on boiling decomposes to give white precipitate of ${MgCO}_{3}$ .
$Mg {({HCO}_{3})}_{2} (aq) \overset{Heat}{⟶} {MgCO}_{3} ↓ + H_{2} O + {CO}_{2} ↑ .$

CHXI10:THE S-BLOCK ELEMENTS

315910 Which does not exists in solid state?

1

{LiHCO}_{3}

2

{CaCO}_{3}

3

{NaHCO}_{3}

4

{Na}_{2} {CO}_{3}

CHXI10:THE S-BLOCK ELEMENTS

315911 Which of the following disproportionate on heating?

1

{Na}_{2} O

2

{Na}_{2} O_{2}

3

BaO

4

{Li}_{2} O

Explanation:

$2 {Na}_{2} O \overset{400^{\circ} C}{⟶} {Na}_{2} O_{2} + 2 Na$ .

CHXI10:THE S-BLOCK ELEMENTS

315912 Among the following, the one that gives pink violet colour to the Bunsen flame is

1

NaCl

2

{BaCl}_{2}

3

CsCl

4

KCl

Explanation:

Potassium salts (i.e. $KCl$ ) impart pinkviolet colour the flame.

CHXI10:THE S-BLOCK ELEMENTS

315915 Which of the following alkali metal carbonate is least stable and decomposes readily?

1

{LiHCO}_{3}

2

{CaCO}_{3}

3

K_{2} {CO}_{3}

4

{Na}_{2} {CO}_{3}

CHXI10:THE S-BLOCK ELEMENTS

315909 A sodium salt of an unknown anion when treated with ${MgCl}_{2}$ gives white precipitate only on boiling. The anion is

1

{SO}_{4}^{2 -}

2

{HCO}_{3}^{-}

3

{CO}_{3}^{2 -}

4

{NO}_{3}^{-}

Explanation:

$Mg {({HCO}_{3})}_{2}$ on boiling decomposes to give white precipitate of ${MgCO}_{3}$ .
$Mg {({HCO}_{3})}_{2} (aq) \overset{Heat}{⟶} {MgCO}_{3} ↓ + H_{2} O + {CO}_{2} ↑ .$

CHXI10:THE S-BLOCK ELEMENTS

315910 Which does not exists in solid state?

1

{LiHCO}_{3}

2

{CaCO}_{3}

3

{NaHCO}_{3}

4

{Na}_{2} {CO}_{3}

CHXI10:THE S-BLOCK ELEMENTS

315911 Which of the following disproportionate on heating?

1

{Na}_{2} O

2

{Na}_{2} O_{2}

3

BaO

4

{Li}_{2} O

Explanation:

$2 {Na}_{2} O \overset{400^{\circ} C}{⟶} {Na}_{2} O_{2} + 2 Na$ .

CHXI10:THE S-BLOCK ELEMENTS

315912 Among the following, the one that gives pink violet colour to the Bunsen flame is

1

NaCl

2

{BaCl}_{2}

3

CsCl

4

KCl

Explanation:

Potassium salts (i.e. $KCl$ ) impart pinkviolet colour the flame.

CHXI10:THE S-BLOCK ELEMENTS

315915 Which of the following alkali metal carbonate is least stable and decomposes readily?

1

{LiHCO}_{3}

2

{CaCO}_{3}

3

K_{2} {CO}_{3}

4

{Na}_{2} {CO}_{3}

CHXI10:THE S-BLOCK ELEMENTS

315909 A sodium salt of an unknown anion when treated with ${MgCl}_{2}$ gives white precipitate only on boiling. The anion is

1

{SO}_{4}^{2 -}

2

{HCO}_{3}^{-}

3

{CO}_{3}^{2 -}

4

{NO}_{3}^{-}

Explanation:

$Mg {({HCO}_{3})}_{2}$ on boiling decomposes to give white precipitate of ${MgCO}_{3}$ .
$Mg {({HCO}_{3})}_{2} (aq) \overset{Heat}{⟶} {MgCO}_{3} ↓ + H_{2} O + {CO}_{2} ↑ .$

CHXI10:THE S-BLOCK ELEMENTS

315910 Which does not exists in solid state?

1

{LiHCO}_{3}

2

{CaCO}_{3}

3

{NaHCO}_{3}

4

{Na}_{2} {CO}_{3}

CHXI10:THE S-BLOCK ELEMENTS

315911 Which of the following disproportionate on heating?

1

{Na}_{2} O

2

{Na}_{2} O_{2}

3

BaO

4

{Li}_{2} O

Explanation:

$2 {Na}_{2} O \overset{400^{\circ} C}{⟶} {Na}_{2} O_{2} + 2 Na$ .

CHXI10:THE S-BLOCK ELEMENTS

315912 Among the following, the one that gives pink violet colour to the Bunsen flame is

1

NaCl

2

{BaCl}_{2}

3

CsCl

4

KCl

Explanation:

Potassium salts (i.e. $KCl$ ) impart pinkviolet colour the flame.

CHXI10:THE S-BLOCK ELEMENTS

315915 Which of the following alkali metal carbonate is least stable and decomposes readily?

1

{LiHCO}_{3}

2

{CaCO}_{3}

3

K_{2} {CO}_{3}

4

{Na}_{2} {CO}_{3}

CHXI10:THE S-BLOCK ELEMENTS

315909 A sodium salt of an unknown anion when treated with ${MgCl}_{2}$ gives white precipitate only on boiling. The anion is

1

{SO}_{4}^{2 -}

2

{HCO}_{3}^{-}

3

{CO}_{3}^{2 -}

4

{NO}_{3}^{-}

Explanation:

$Mg {({HCO}_{3})}_{2}$ on boiling decomposes to give white precipitate of ${MgCO}_{3}$ .
$Mg {({HCO}_{3})}_{2} (aq) \overset{Heat}{⟶} {MgCO}_{3} ↓ + H_{2} O + {CO}_{2} ↑ .$

CHXI10:THE S-BLOCK ELEMENTS

315910 Which does not exists in solid state?

1

{LiHCO}_{3}

2

{CaCO}_{3}

3

{NaHCO}_{3}

4

{Na}_{2} {CO}_{3}

CHXI10:THE S-BLOCK ELEMENTS

315911 Which of the following disproportionate on heating?

1

{Na}_{2} O

2

{Na}_{2} O_{2}

3

BaO

4

{Li}_{2} O

Explanation:

$2 {Na}_{2} O \overset{400^{\circ} C}{⟶} {Na}_{2} O_{2} + 2 Na$ .

CHXI10:THE S-BLOCK ELEMENTS

315912 Among the following, the one that gives pink violet colour to the Bunsen flame is

1

NaCl

2

{BaCl}_{2}

3

CsCl

4

KCl

Explanation:

Potassium salts (i.e. $KCl$ ) impart pinkviolet colour the flame.