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CHXI11:THE P-BLOCK ELEMENTS

316822 Reaction of thionyl chloride with white phosphorus forms a compound [A], which on hydrolysis gives [B], a dibasic acid. [A] and [B] are respectively

1

{POCl}_{3}

and

H_{3} {PO}_{4}

2

{PCl}_{5}

and

H_{3} {PO}_{4}

3

{PCl}_{3}

and

H_{3} {PO}_{3}

4

P_{4} O_{6}

and

H_{3} {PO}_{3}

Explanation:

White phosphorus reacts with thionyl chloride to form ${PCl}_{3}$ :
$P_{4} + 8 {SOCl}_{2} ⟶ \underset{[A]}{4 {PCl}_{3}} + 4 {SO}_{2} + 2 S_{2} {Cl}_{2}$
${PCl}_{3}$ hydrolyses in presence of moisture:
$P C l_{3} + 3 H_{2} O \to \underset{[B]}{H_{3} P O_{3}} + 3 H C l$
Thus, option (3) is the correct choice.

JEE - 2023

CHXI11:THE P-BLOCK ELEMENTS

316823 Consider the following statements regarding phosphours,
I. Phosphorous exists in different allotropic forms.
II. Yellow phosphorus exists as tetrahedral molecular solid.
III. Yellow phosphorus is less reactive than red phosphorus.
IV. Yellow phosphorus has layered type structure.
The correct statements are

1 I, II and IV

2 I, II and III

3 II, III and IV

4 I, III and IV

CHXI11:THE P-BLOCK ELEMENTS

316824 On heating with concentrated $NaOH$ solution in an inert atmosphere of ${CO}_{2}$ , white phosphorus gives a gas. Which of the following statement is incorrect about the gas?

1 It is highly poisonous and smells like rotten fish.

2 It's solution in water decomposes in the presence of light.

3 It is more basic than

{NH}_{3}

.

4 It is less basic than

{NH}_{3}

.

Explanation:

$P_{4} + 3 NaOH + 3 H_{2} O \to {PH}_{3} + \underset{(sodium hypophosphite)}{3 {NaH}_{2} {PO}_{2}}$
Phosphine gas is less basic than ${NH}_{3}$ .

CHXI11:THE P-BLOCK ELEMENTS

316825 Assertion :
White phosphorus is also called yellow phosphorus.
Reason :
White phosphorus is soluble in ${CS}_{2}$ .

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:

When exposed to light, white phosphorus undergoes a transformation, turning into a yellowish form. White $P_{4}$ is soluble in ${CS}_{2}$ . But it is not the correct explanation of the given assertion. So option (2) is correct.

CHXI11:THE P-BLOCK ELEMENTS

316822 Reaction of thionyl chloride with white phosphorus forms a compound [A], which on hydrolysis gives [B], a dibasic acid. [A] and [B] are respectively

1

{POCl}_{3}

and

H_{3} {PO}_{4}

2

{PCl}_{5}

and

H_{3} {PO}_{4}

3

{PCl}_{3}

and

H_{3} {PO}_{3}

4

P_{4} O_{6}

and

H_{3} {PO}_{3}

Explanation:

White phosphorus reacts with thionyl chloride to form ${PCl}_{3}$ :
$P_{4} + 8 {SOCl}_{2} ⟶ \underset{[A]}{4 {PCl}_{3}} + 4 {SO}_{2} + 2 S_{2} {Cl}_{2}$
${PCl}_{3}$ hydrolyses in presence of moisture:
$P C l_{3} + 3 H_{2} O \to \underset{[B]}{H_{3} P O_{3}} + 3 H C l$
Thus, option (3) is the correct choice.

JEE - 2023

CHXI11:THE P-BLOCK ELEMENTS

316823 Consider the following statements regarding phosphours,
I. Phosphorous exists in different allotropic forms.
II. Yellow phosphorus exists as tetrahedral molecular solid.
III. Yellow phosphorus is less reactive than red phosphorus.
IV. Yellow phosphorus has layered type structure.
The correct statements are

1 I, II and IV

2 I, II and III

3 II, III and IV

4 I, III and IV

CHXI11:THE P-BLOCK ELEMENTS

316824 On heating with concentrated $NaOH$ solution in an inert atmosphere of ${CO}_{2}$ , white phosphorus gives a gas. Which of the following statement is incorrect about the gas?

1 It is highly poisonous and smells like rotten fish.

2 It's solution in water decomposes in the presence of light.

3 It is more basic than

{NH}_{3}

.

4 It is less basic than

{NH}_{3}

.

Explanation:

$P_{4} + 3 NaOH + 3 H_{2} O \to {PH}_{3} + \underset{(sodium hypophosphite)}{3 {NaH}_{2} {PO}_{2}}$
Phosphine gas is less basic than ${NH}_{3}$ .

CHXI11:THE P-BLOCK ELEMENTS

316825 Assertion :
White phosphorus is also called yellow phosphorus.
Reason :
White phosphorus is soluble in ${CS}_{2}$ .

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:

When exposed to light, white phosphorus undergoes a transformation, turning into a yellowish form. White $P_{4}$ is soluble in ${CS}_{2}$ . But it is not the correct explanation of the given assertion. So option (2) is correct.

CHXI11:THE P-BLOCK ELEMENTS

316822 Reaction of thionyl chloride with white phosphorus forms a compound [A], which on hydrolysis gives [B], a dibasic acid. [A] and [B] are respectively

1

{POCl}_{3}

and

H_{3} {PO}_{4}

2

{PCl}_{5}

and

H_{3} {PO}_{4}

3

{PCl}_{3}

and

H_{3} {PO}_{3}

4

P_{4} O_{6}

and

H_{3} {PO}_{3}

Explanation:

White phosphorus reacts with thionyl chloride to form ${PCl}_{3}$ :
$P_{4} + 8 {SOCl}_{2} ⟶ \underset{[A]}{4 {PCl}_{3}} + 4 {SO}_{2} + 2 S_{2} {Cl}_{2}$
${PCl}_{3}$ hydrolyses in presence of moisture:
$P C l_{3} + 3 H_{2} O \to \underset{[B]}{H_{3} P O_{3}} + 3 H C l$
Thus, option (3) is the correct choice.

JEE - 2023

CHXI11:THE P-BLOCK ELEMENTS

316823 Consider the following statements regarding phosphours,
I. Phosphorous exists in different allotropic forms.
II. Yellow phosphorus exists as tetrahedral molecular solid.
III. Yellow phosphorus is less reactive than red phosphorus.
IV. Yellow phosphorus has layered type structure.
The correct statements are

1 I, II and IV

2 I, II and III

3 II, III and IV

4 I, III and IV

CHXI11:THE P-BLOCK ELEMENTS

316824 On heating with concentrated $NaOH$ solution in an inert atmosphere of ${CO}_{2}$ , white phosphorus gives a gas. Which of the following statement is incorrect about the gas?

1 It is highly poisonous and smells like rotten fish.

2 It's solution in water decomposes in the presence of light.

3 It is more basic than

{NH}_{3}

.

4 It is less basic than

{NH}_{3}

.

Explanation:

$P_{4} + 3 NaOH + 3 H_{2} O \to {PH}_{3} + \underset{(sodium hypophosphite)}{3 {NaH}_{2} {PO}_{2}}$
Phosphine gas is less basic than ${NH}_{3}$ .

CHXI11:THE P-BLOCK ELEMENTS

316825 Assertion :
White phosphorus is also called yellow phosphorus.
Reason :
White phosphorus is soluble in ${CS}_{2}$ .

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:

When exposed to light, white phosphorus undergoes a transformation, turning into a yellowish form. White $P_{4}$ is soluble in ${CS}_{2}$ . But it is not the correct explanation of the given assertion. So option (2) is correct.

CHXI11:THE P-BLOCK ELEMENTS

316822 Reaction of thionyl chloride with white phosphorus forms a compound [A], which on hydrolysis gives [B], a dibasic acid. [A] and [B] are respectively

1

{POCl}_{3}

and

H_{3} {PO}_{4}

2

{PCl}_{5}

and

H_{3} {PO}_{4}

3

{PCl}_{3}

and

H_{3} {PO}_{3}

4

P_{4} O_{6}

and

H_{3} {PO}_{3}

Explanation:

White phosphorus reacts with thionyl chloride to form ${PCl}_{3}$ :
$P_{4} + 8 {SOCl}_{2} ⟶ \underset{[A]}{4 {PCl}_{3}} + 4 {SO}_{2} + 2 S_{2} {Cl}_{2}$
${PCl}_{3}$ hydrolyses in presence of moisture:
$P C l_{3} + 3 H_{2} O \to \underset{[B]}{H_{3} P O_{3}} + 3 H C l$
Thus, option (3) is the correct choice.

JEE - 2023

CHXI11:THE P-BLOCK ELEMENTS

316823 Consider the following statements regarding phosphours,
I. Phosphorous exists in different allotropic forms.
II. Yellow phosphorus exists as tetrahedral molecular solid.
III. Yellow phosphorus is less reactive than red phosphorus.
IV. Yellow phosphorus has layered type structure.
The correct statements are

1 I, II and IV

2 I, II and III

3 II, III and IV

4 I, III and IV

CHXI11:THE P-BLOCK ELEMENTS

316824 On heating with concentrated $NaOH$ solution in an inert atmosphere of ${CO}_{2}$ , white phosphorus gives a gas. Which of the following statement is incorrect about the gas?

1 It is highly poisonous and smells like rotten fish.

2 It's solution in water decomposes in the presence of light.

3 It is more basic than

{NH}_{3}

.

4 It is less basic than

{NH}_{3}

.

Explanation:

$P_{4} + 3 NaOH + 3 H_{2} O \to {PH}_{3} + \underset{(sodium hypophosphite)}{3 {NaH}_{2} {PO}_{2}}$
Phosphine gas is less basic than ${NH}_{3}$ .

CHXI11:THE P-BLOCK ELEMENTS

316825 Assertion :
White phosphorus is also called yellow phosphorus.
Reason :
White phosphorus is soluble in ${CS}_{2}$ .

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:

When exposed to light, white phosphorus undergoes a transformation, turning into a yellowish form. White $P_{4}$ is soluble in ${CS}_{2}$ . But it is not the correct explanation of the given assertion. So option (2) is correct.