White Phosphorous PYQs MCQs

White Phosphorous MCQs
NEET, IIT-JEE, CSIR-NET, GATE, IIT-JAM

NEET 2022, 2023 Repeated

Question: White phosphorus is stored under

1. water
2. kerosene
3. CS₂
4. alcohol

Correct Answer: A

Explanation: White P ignites spontaneously in air at ~30°C. Water excludes air and prevents oxidation.

JEE Main 2021

Question: White phosphorus glows in the dark due to

1. chemiluminescence
2. fluorescence
3. phosphorescence
4. triboluminescence

Correct Answer: A

Explanation: Slow oxidation of P₄ in air produces excited molecules that emit greenish light → chemiluminescence.

JEE Advanced 2019

Question: The bond angle in P₄ molecule of white phosphorus is

1. 109°28'
2. 90°
3. 60°
4. 120°

Correct Answer: C

Explanation: Regular tetrahedron → bond angle = 60°. High angle strain makes it extremely reactive.

NEET 2020

Question: White phosphorus has

1. garlic odour
2. no odour
3. pleasant odour
4. fishy odour

Correct Answer: A

JEE Main

Question: White phosphorus is

1. molecular solid (P₄)
2. ionic solid
3. metallic solid
4. covalent network solid

Correct Answer: A

NEET Repeated

Question: White phosphorus is highly poisonous and causes

1. phossy jaw
2. minamata disease
3. black foot disease
4. itai-itai disease

Correct Answer: A

Explanation: Chronic poisoning → necrosis of jaw bone → “phossy jaw”.

JEE Advanced & CSIR-NET

Question: Reaction of white P with hot conc. NaOH gives

1. PH₃ + Na₃PO₄
2. PH₃ + NaH₂PO₂
3. P₂H₄ only
4. H₃PO₄ only

Correct Answer: B

Explanation: P₄ + 3NaOH + 3H₂O → PH₃ + 3NaH₂PO₂ (disproportionation)

NEET

Question: Ignition temperature of white phosphorus is about

1. 30°C
2. 260°C
3. 573 K
4. 416°C

Correct Answer: A

JEE Main

Question: White phosphorus is soluble in

1. water
2. CS₂
3. alcohol only
4. none

Correct Answer: B

NEET 2021

Question: White phosphorus was used in old “strike-anywhere” matches because

1. it ignites at very low temperature
2. it is non-poisonous
3. it has high ignition temperature
4. it is insoluble in CS₂

Correct Answer: A

Explanation: Later banned due to toxicity.

JEE Advanced

Question: Number of P–P bonds in P₄ molecule is

1. 4
2. 6
3. 8
4. 12

Correct Answer: B

GATE / CSIR-NET

Question: In P₄ molecule, hybridization of phosphorus is

1. sp
2. sp²
3. sp³
4. sp³d

Correct Answer: C

NEET

Question: White phosphorus is manufactured by heating

1. phosphate rock + coke + sand in electric furnace
2. bone ash + H₂SO₄
3. red P at 573 K
4. P₄O₁₀ with water

Correct Answer: A

JEE Main

Question: Which allotrope of phosphorus is most reactive?

1. Red
2. White
3. Black
4. Violet

Correct Answer: B

JEE Advanced

Question: Conversion of white P → red P is

1. exothermic and irreversible
2. endothermic and reversible
3. exothermic but reversible
4. endothermic and irreversible

Correct Answer: A

NEET

Question: White phosphorus reacts with conc. HNO₃ to form

1. H₃PO₃
2. H₃PO₄
3. HPO₃
4. P₂O₅

Correct Answer: B

JEE Main

Question: White phosphorus is also known as

1. yellow phosphorus
2. red phosphorus
3. black phosphorus
4. scarlet phosphorus

Correct Answer: A

CSIR-NET

Question: The colour of glow of white phosphorus in dark is

1. greenish
2. bluish
3. yellow
4. red

Correct Answer: A

NEET

Question: White phosphorus is used in

1. rat poison
2. smoke screens
3. incendiary bombs
4. all of these

Correct Answer: D

JEE Main

Question: Melting point of white phosphorus is

1. 44.2°C
2. 260°C
3. 590°C
4. 416°C

Correct Answer: A

JEE Advanced

Question: In P₄, each P atom has

1. 3 bond pairs + 1 lone pair
2. 4 bond pairs
3. 2 bond pairs + 2 lone pairs
4. 3 bond pairs only

Correct Answer: A

GATE

Question: White phosphorus on exposure to air forms

1. P₄O₆
2. P₄O₁₀
3. H₃PO₄
4. both A and B

Correct Answer: D

NEET

Question: Which is incorrect for white phosphorus?

1. Insoluble in water
2. Polymeric structure
3. Highly poisonous
4. Glows in dark

Correct Answer: B

Explanation: It has discrete P₄ molecules, not polymeric.

JEE Main

Question: White phosphorus is less stable than red phosphorus because of

1. angle strain in P₄
2. high density
3. polymeric nature
4. non-poisonous nature

Correct Answer: A

CSIR-NET

Question: The oxidation state of P in PH₃ produced from white P + NaOH is

1. –3
2. +3
3. +1
4. 0

Correct Answer: A

NEET

Question: White phosphorus has

1. six P–P single bonds
2. four P–P single bonds
3. six P=P bonds
4. no P–P bonds

Correct Answer: A

JEE Advanced

Question: White phosphorus is waxy because of

1. low melting point and molecular nature
2. high density
3. polymeric chains
4. ionic bonding

Correct Answer: A

GATE

Question: The industrial preparation of white phosphorus involves

1. electric furnace
2. blast furnace
3. open hearth furnace
4. reverberatory furnace

Correct Answer: A

NEET / JEE Main

Question: Which allotrope of phosphorus is kept under water?

1. Red P
2. White P
3. Black P
4. All

Correct Answer: B

Must Read White Phosphorus: Preparation, Properties, Structure, and Uses

Related Topics
White Phosphorus
Red Phosphorus
Black Phosphorus
White Phosphorus PYQs MCQs
Red Phosphorus PYQs MCQs
Black Phosphorus PYQs MCQs