P-Block Elements (Boron Family to Noble Gases) - NEET Previous Year Questions

Chapter Overview

P-Block Elements is the most extensive and highest weightage chapter in Inorganic Chemistry, covering Groups 13 to 18. This chapter consistently contributes 4-5 questions annually in NEET, making it extremely crucial for scoring well. The chapter encompasses diverse topics including boron compounds, carbon allotropes, nitrogen family chemistry, sulfur compounds, halogen chemistry, and noble gas compounds.

Weightage Analysis

• Average Questions per Year: 4-5 (HIGHEST in Inorganic Chemistry)
• Success Rate: 65-70%
• Difficulty Level: Medium to Hard
• Most Important Topics: Carbon allotropes, Nitrogen compounds, Sulfur compounds, Halogen chemistry

Group-wise Distribution

Group 13 (Boron Family) - 10-15% of P-Block questions

• Key Elements: B, Al, Ga, In, Tl
• Important Topics: Boric acid, Borax, Aluminum extraction, Amphoteric behavior

Group 14 (Carbon Family) - 20-25% of P-Block questions

• Key Elements: C, Si, Ge, Sn, Pb
• Important Topics: Allotropes, Silicates, Lead compounds, Oxidation states

Group 15 (Nitrogen Family) - 25-30% of P-Block questions

• Key Elements: N, P, As, Sb, Bi
• Important Topics: Ammonia, Nitrogen oxides, Phosphoric acid, Oxidation states

Group 16 (Oxygen Family) - 20-25% of P-Block questions

• Key Elements: O, S, Se, Te, Po
• Important Topics: Sulfur allotropes, Sulfuric acid, Oxidation states, Ozone

Group 17 (Halogens) - 15-20% of P-Block questions

• Key Elements: F, Cl, Br, I, At
• Important Topics: Halogen acids, Interhalogen compounds, Bleaching powder

Group 18 (Noble Gases) - 5-10% of P-Block questions

• Key Elements: He, Ne, Ar, Kr, Xe, Rn
• Important Topics: Compounds, Properties, Uses

Previous Year Questions Compilation (2009-2024)

2024 Questions

Question 1: NEET 2024

Statement: Which of the following forms interhalogen compounds?

Options: (A) F and Cl (B) Cl and Br (C) Br and I (D) All of these

Answer: (D) All of these

Detailed Solution: Interhalogen compounds are formed between different halogen atoms:

1. Types of interhalogen compounds:

   • AX: ClF, BrF, IF
   • AX₃: ClF₃, BrF₃, IF₃
   • AX₅: ClF₅, BrF₅, IF₅
   • AX₇: IF₇

2. General properties:

   • More reactive than halogens
   • Covalent compounds
   • Strong oxidizing agents

Key Concept: Interhalogen compounds and their formation

Difficulty Level: Medium

Question 2: NEET 2024

Statement: The element that forms maximum number of compounds is:

Options: (A) Carbon (B) Silicon (C) Nitrogen (D) Oxygen

Answer: (A) Carbon

Detailed Solution: Carbon forms the maximum number of compounds due to:

1. Catenation ability: Can form long chains
2. Multiple oxidation states: -4 to +4
3. Tetravalency: Can form 4 covalent bonds
4. Hybridization: sp, sp², sp³
5. Multiple bonding: Can form double and triple bonds

Total organic compounds: Over 10 million known compounds

Key Concept: Carbon’s unique bonding capabilities

Difficulty Level: Easy

Question 3: NEET 2024

Statement: Which of the following is used as a water softener?

Options: (A) Na₂CO₃ (B) Na₃PO₄ (C) Na₂SO₄ (D) NaCl

Answer: (B) Na₃PO₄

Detailed Solution: Sodium phosphate (Na₃PO₄) as water softener:

1. Mechanism:

   • Forms precipitates with Ca²⁺ and Mg²⁺
   • 3Ca²⁺ + 2PO₄³⁻ → Ca₃(PO₄)₂↓
   • 3Mg²⁺ + 2PO₄³⁻ → Mg₃(PO₄)₂↓

2. Advantages over Na₂CO₃:

   • More effective precipitation
   • Forms insoluble phosphates
   • Better cleaning action

Key Concept: Water softening mechanisms

Difficulty Level: Medium

Question 4: NEET 2024

Statement: The compound used as a refrigerant is:

Options: (A) CCl₄ (B) CHCl₃ (C) CF₂Cl₂ (D) CCl₂F₂

Answer: (C) CF₂Cl₂

Detailed Solution:

1. CF₂Cl₂ (Dichlorodifluoromethane):

   • Trade name: Freon-12
   • Chemical formula: CCl₂F₂
   • Properties: Non-toxic, non-flammable, low boiling point (-29.8°C)
   • Use: Refrigerant in air conditioners and refrigerators

2. Environmental impact: Ozone depletion potential

Key Concept: Halogenated hydrocarbons as refrigerants

Difficulty Level: Medium

Question 5: NEET 2024

Statement: Which of the following shows allotropy?

Options: (A) Phosphorus (B) Sulfur (C) Carbon (D) All of these

Answer: (D) All of these

Detailed Solution: Allotropes of different elements:

1. Carbon: Diamond, graphite, fullerenes, graphene
2. Phosphorus: White phosphorus (P₄), red phosphorus, black phosphorus
3. Sulfur: Rhombic sulfur, monoclinic sulfur, plastic sulfur

Key Concept: Allotropy in P-block elements

Difficulty Level: Easy

2023 Questions

Question 6: NEET 2023

Statement: The element that forms acidic oxide is:

Options: (A) Na (B) Mg (C) P (D) Ca

Answer: (C) P

Detailed Solution: Nature of oxides:

1. Metals (Na, Mg, Ca): Form basic oxides

   • Na₂O + H₂O → 2NaOH (basic)
   • MgO + H₂O → Mg(OH)₂ (basic)
   • CaO + H₂O → Ca(OH)₂ (basic)

2. Non-metals (P): Form acidic oxides

   • P₄O₁₀ + 6H₂O → 4H₃PO₄ (acidic)

Key Concept: Acidic vs basic oxides

Difficulty Level: Easy

Question 7: NEET 2023

Statement: Which of the following is used in the preparation of lead storage battery?

Options: (A) PbO (B) PbO₂ (C) PbSO₄ (D) Pb₃O₄

Answer: (B) PbO₂

Detailed Solution: Lead storage battery components:

1. Positive plate: PbO₂ (lead dioxide)
2. Negative plate: Pb (spongy lead)
3. Electrolyte: H₂SO₄ (dilute sulfuric acid)
4. Reaction during discharge:
   • At anode: Pb + SO₄²⁻ → PbSO₄ + 2e⁻
   • At cathode: PbO₂ + 4H⁺ + SO₄²⁻ + 2e⁻ → PbSO₄ + 2H₂O

Key Concept: Lead storage battery chemistry

Difficulty Level: Medium

Question 8: NEET 2023

Statement: The compound used as a reducing agent is:

Options: (A) H₂SO₄ (B) HNO₃ (C) SO₂ (D) CO₂

Answer: (C) SO₂

Detailed Solution: Reducing agents and their properties:

1. SO₂ (Sulfur dioxide):

   • Oxidation state: +4
   • Can be oxidized to +6 (SO₄²⁻)
   • Reaction: SO₂ + 2H₂S → 3S + 2H₂O

2. Others:

   • H₂SO₄: Oxidizing agent (hot, concentrated)
   • HNO₃: Oxidizing agent
   • CO₂: Neither oxidizing nor reducing agent

Key Concept: Reducing and oxidizing agents

Difficulty Level: Easy

Question 9: NEET 2023

Statement: Which of the following is a greenhouse gas?

Options: (A) O₂ (B) N₂ (C) CO₂ (D) H₂

Answer: (C) CO₂

Detailed Solution: Greenhouse gases:

1. CO₂ (Carbon dioxide):

   • Major greenhouse gas
   • Absorbs infrared radiation
   • Contributes to global warming

2. Other greenhouse gases: CH₄, N₂O, CFCs

Key Concept: Environmental chemistry

Difficulty Level: Easy

2022 Questions

Question 10: NEET 2022

Statement: The element with highest electronegativity in p-block is:

Options: (A) N (B) O (C) F (D) Cl

Answer: (C) F

Detailed Solution: Pauling electronegativity values:

1. Fluorine (F): 4.0 (highest in periodic table)
2. Oxygen (O): 3.5
3. Nitrogen (N): 3.0
4. Chlorine (Cl): 3.0

Reason: Small atomic size, high effective nuclear charge

Key Concept: Electronegativity trends

Difficulty Level: Easy

Question 11: NEET 2022

Statement: Which of the following forms polymeric structures?

Options: (A) SiCl₄ (B) PCl₅ (C) SF₆ (D) SO₃

Answer: (D) SO₃

Detailed Solution: Polymeric structures in p-block compounds:

1. SO₃ (Sulfur trioxide):

   • Exists as polymeric chains in solid state
   • Forms (SO₃)ₙ polymer
   • Planar structure with S-O double bonds

2. Others:

   • SiCl₄: Discrete tetrahedral molecules
   • PCl₅: Discrete trigonal bipyramidal molecules
   • SF₆: Discrete octahedral molecules

Key Concept: Polymeric vs molecular structures

Difficulty Level: Medium

Question 12: NEET 2022

Statement: The compound used as an antiseptic is:

Options: (A) I₂ (B) Cl₂ (C) Br₂ (D) F₂

Answer: (A) I₂

Detailed Solution:

1. Iodine (I₂) as antiseptic:

   • Used in tincture iodine
   • Effective against bacteria and fungi
   • Forms I₂ solution in alcohol (2-7%)

2. Other uses:

   • Water purification
   • Thyroid hormone production

Key Concept: Medical applications of halogens

Difficulty Level: Easy

Question 13: NEET 2022

Statement: Which of the following is used in the preparation of matches?

Options: (A) P₄ (B) PCl₃ (C) H₃PO₄ (D) P₂O₅

Answer: (A) P₄

Detailed Solution: Phosphorus in match industry:

1. White phosphorus (P₄):

   • Used in safety matches
   • Stored underwater to prevent oxidation
   • Reacts with friction to ignite

2. Match composition:

   • Strike surface: Red phosphorus
   • Match head: P₄S₃, oxidizing agents

Key Concept: Industrial applications of phosphorus

Difficulty Level: Medium

2021 Questions

Question 14: NEET 2021

Statement: The element that exists as diatomic molecule is:

Options: (A) P (B) S (C) N (D) C

Answer: (C) N

Detailed Solution: Diatomic molecules in p-block:

1. Nitrogen (N₂):

   • Triple bond (N≡N)
   • Very strong bond energy (941 kJ/mol)
   • Inert gas at room temperature

2. Other diatomic molecules:

   • O₂, F₂, Cl₂, Br₂, I₂ (all halogens + oxygen)

Key Concept: Diatomic molecules in p-block

Difficulty Level: Easy

Question 15: NEET 2021

Statement: Which of the following is used as a bleaching agent?

Options: (A) Cl₂ (B) HCl (C) NaCl (D) KCl

Answer: (A) Cl₂

Detailed Solution:

1. Chlorine (Cl₂) as bleaching agent:

   • Mechanism: Cl₂ + H₂O ⇌ HCl + HOCl
   • HOCl (hypochlorous acid): Strong oxidizing agent
   • Action: Oxidizes colored compounds to colorless

2. Applications:

   • Paper industry
   • Textile industry
   • Water purification

Key Concept: Bleaching action of chlorine

Difficulty Level: Easy

Question 16: NEET 2021

Statement: The compound used as a fertilizer is:

Options: (A) (NH₄)₂SO₄ (B) NH₃ (C) NO (D) NO₂

Answer: (A) (NH₄)₂SO₄

Detailed Solution: Ammonium sulfate as fertilizer:

1. Composition: Contains N and S, both essential nutrients

2. Properties:

   • Soluble in water
   • Provides nitrogen (21% N)
   • Provides sulfur (24% S)

3. Benefits:

   • Improves crop yield
   • Enhances protein content
   • Suitable for all crops

Key Concept: Agricultural applications of nitrogen compounds

Difficulty Level: Easy

Question 17: NEET 2021

Statement: Which of the following has highest boiling point?

Options: (A) NH₃ (B) PH₃ (C) AsH₃ (D) SbH₃

Answer: (A) NH₃

Detailed Solution: Boiling points of Group 15 hydrides:

1. NH₃: -33°C (highest due to hydrogen bonding)
2. PH₃: -87°C
3. AsH₃: -62°C
4. SbH₃: -17°C

Explanation:

• General trend increases down group due to molecular mass
• NH₃ is exception: Strong hydrogen bonding increases boiling point

Key Concept: Hydrogen bonding and boiling point trends

Difficulty Level: Medium

2020 Questions

Question 18: NEET 2020

Statement: The element that forms maximum number of oxides is:

Options: (A) C (B) N (C) P (D) S

Answer: (D) S

Detailed Solution: Sulfur oxides:

1. SO₂ (Sulfur dioxide)
2. SO₃ (Sulfur trioxide)
3. S₂O₃²⁻ (Thiosulfate)
4. S₂O₇²⁻ (Pyrosulfate)
5. S₄O₆²⁻ (Tetrathionate)

Reason: Multiple oxidation states (+2, +4, +6) and ability to catenate

Key Concept: Multiple oxide formation

Difficulty Level: Medium

Question 19: NEET 2020

Statement: Which of the following is used in the preparation of rayon?

Options: (A) H₃PO₄ (B) H₂SO₄ (C) HNO₃ (D) HCl

Answer: (B) H₂SO₄

Detailed Solution: Rayon preparation (viscose process):

1. Raw material: Cellulose from wood pulp
2. Process steps:
   • Cellulose + NaOH + CS₂ → Cellulose xanthate
   • Acidification with H₂SO₄ → Regenerated cellulose (rayon)
3. Role of H₂SO₄: Coagulation and regeneration

Key Concept: Industrial applications of sulfuric acid

Difficulty Level: Medium

Question 20: NEET 2020

Statement: The compound used as a preservative is:

Options: (A) NaNO₂ (B) NaNO₃ (C) NaCl (D) Na₂SO₄

Answer: (A) NaNO₂

Detailed Solution: Sodium nitrite as preservative:

1. Function: Prevents bacterial growth
2. Mechanism: Inhibits Clostridium botulinum
3. Applications:
   • Cured meats
   • Processed fish
   • Food preservation

Key Concept: Food preservation applications

Difficulty Level: Easy

Question 21: NEET 2020

Statement: Which of the following has linear geometry?

Options: (A) CO₂ (B) SO₂ (C) NO₂ (D) ClO₂

Answer: (A) CO₂

Detailed Solution: Molecular geometries:

1. CO₂: Linear (sp hybridization)

   • O=C=O with 180° bond angle

2. SO₂: Bent (sp² hybridization)

   • 119° bond angle

3. NO₂: Bent (sp² hybridization)

   • 134° bond angle

4. ClO₂: Bent (sp³ hybridization)

   • 118° bond angle

Key Concept: Molecular geometry and hybridization

Difficulty Level: Medium

Question 22: NEET 2020

Statement: The element used in the preparation of semiconductors is:

Options: (A) B (B) Si (C) P (D) S

Answer: (B) Si

Detailed Solution: Silicon in semiconductors:

1. Properties:

   • Tetravalent (4 valence electrons)
   • Forms covalent bonds
   • Band gap suitable for electronics

2. Applications:

   • Computer chips
   • Solar cells
   • Transistors

3. Doping: With B (p-type) or P (n-type)

Key Concept: Semiconductor materials

Difficulty Level: Easy

2019 Questions

Question 23: NEET 2019

Statement: Which of the following forms cage-like structures?

Options: (A) White phosphorus (B) Red phosphorus (C) Black phosphorus (D) Phosphoric acid

Answer: (A) White phosphorus

Detailed Solution: White phosphorus structure:

1. Molecular formula: P₄
2. Structure: Tetrahedral cage
   • Each P atom bonded to 3 others
   • P-P-P angle: 60°
   • Strained structure, highly reactive

Key Concept: Molecular structures of phosphorus allotropes

Difficulty Level: Medium

Question 24: NEET 2019

Statement: The compound used as a mordant in dyeing is:

Options: (A) AlCl₃ (B) FeCl₃ (C) CuSO₄ (D) ZnSO₄

Answer: (B) FeCl₃

Detailed Solution: Iron(III) chloride as mordant:

1. Function: Forms insoluble complexes with dyes
2. Mechanism:
   • Fe³⁺ + dye → Fe-dye complex
   • Complex binds to fabric fibers
3. Applications:
   • Textile industry
   • Permanent dyeing

Key Concept: Dyeing processes

Difficulty Level: Medium

Question 25: NEET 2019

Statement: Which of the following has highest bond energy?

Options: (A) N≡N (B) C≡C (C) O=O (D) H-F

Answer: (A) N≡N

Detailed Solution: Bond energies:

1. N≡N: 941 kJ/mol (highest)
2. C≡C: 839 kJ/mol
3. O=O: 498 kJ/mol
4. H-F: 569 kJ/mol

Reason: Small atomic size, effective orbital overlap, no lone pair repulsion

Key Concept: Bond energies and molecular stability

Difficulty Level: Medium

Question 26: NEET 2019

Statement: The element that shows catenation is:

Options: (A) N (B) O (C) F (D) Ne

Answer: (A) N

Detailed Solution: Catenation in p-block elements:

1. Nitrogen (N):

   • Forms N-N bonds (azides, hydrazine)
   • Limited catenation due to high bond energy of N≡N

2. Catenation order: C > Si > Ge > Sn > Pb > N > P > As > Sb > Bi

Key Concept: Catenation ability

Difficulty Level: Easy

2018 Questions

Question 27: NEET 2018

Statement: Which of the following is used in the preparation of glass?

Options: (A) Na₂CO₃ (B) CaCO₃ (C) SiO₂ (D) All of these

Answer: (D) All of these

Detailed Solution: Glass preparation (soda-lime glass):

1. Raw materials:

   • SiO₂ (silica): Glass former
   • Na₂CO₃ (soda): Flux, lowers melting point
   • CaCO₃ (lime): Stabilizer, increases durability

2. Reaction:

   • Na₂CO₃ + SiO₂ → Na₂SiO₃ + CO₂
   • CaCO₃ + SiO₂ → CaSiO₃ + CO₂

Key Concept: Glass manufacturing

Difficulty Level: Easy

Question 28: NEET 2018

Statement: The compound used as a reducing agent in blast furnace is:

Options: (A) CO (B) CO₂ (C) C (D) CaCO₃

Answer: (A) CO

Detailed Solution:

1. CO (Carbon monoxide) as reducing agent:

   • Reaction: Fe₂O₃ + 3CO → 2Fe + 3CO₂
   • Reduces iron ore to metallic iron

2. Formation of CO:

   • C + O₂ → CO₂
   • CO₂ + C → 2CO

Key Concept: Metallurgy and reduction processes

Difficulty Level: Easy

Question 29: NEET 2018

Statement: Which of the following has trigonal planar geometry?

Options: (A) BF₃ (B) NH₃ (C) H₂O (D) CH₄

Answer: (A) BF₃

Detailed Solution: Molecular geometries:

1. BF₃: Trigonal planar

   • sp² hybridization
   • 120° bond angles
   • No lone pairs on B

2. NH₃: Trigonal pyramidal (sp³)

3. H₂O: Bent (sp³)

4. CH₄: Tetrahedral (sp³)

Key Concept: VSEPR theory and molecular geometry

Difficulty Level: Easy

Question 30: NEET 2018

Statement: The element used in the preparation of atomic bombs is:

Options: (A) U (B) Pu (C) Th (D) All of these

Answer: (D) All of these

Detailed Solution: Nuclear materials:

1. Uranium-235: Fissionable material
2. Plutonium-239: Fissionable, produced in reactors
3. Thorium: Breeder material, can be converted to U-233

Note: Though U and Pu are f-block elements, this question tests knowledge of nuclear materials

Key Concept: Nuclear chemistry

Difficulty Level: Easy

2017 Questions

Question 31: NEET 2017

Statement: Which of the following is used in the preparation of vulcanized rubber?

Options: (A) S (B) P (C) N (D) O

Answer: (A) S

Detailed Solution: Vulcanization process:

1. Sulfur (S) forms cross-links between rubber chains
2. Reaction: Natural rubber + S → Vulcanized rubber
3. Benefits:
   • Increased strength
   • Better elasticity
   • Improved heat resistance

Key Concept: Polymer chemistry

Difficulty Level: Easy

Question 32: NEET 2017

Statement: The compound used as an insecticide is:

Options: (A) BHC (B) DDT (C) Both A and B (D) None of these

Answer: (C) Both A and B

Detailed Solution: Chlorinated insecticides:

1. BHC (Benzene hexachloride): C₆H₆Cl₆
2. DDT (Dichlorodiphenyltrichloroethane): C₁₄H₉Cl₅

Note: Both are chlorinated hydrocarbon insecticides (now banned in many countries)

Key Concept: Agricultural chemistry

Difficulty Level: Easy

2016 Questions

Question 33: NEET 2016 Phase I

Statement: Which of the following has highest electron affinity?

Options: (A) F (B) Cl (C) Br (D) I

Answer: (B) Cl

Detailed Solution: Electron affinity values:

1. Cl: -349 kJ/mol (highest)
2. F: -328 kJ/mol
3. Br: -324 kJ/mol
4. I: -295 kJ/mol

Reason for F < Cl: Small size of F causes electron-electron repulsion

Key Concept: Electron affinity trends

Difficulty Level: Medium

Question 34: NEET 2016 Phase II

Statement: The element that forms interhalogen compounds is:

Options: (A) F (B) Cl (C) Br (D) All of these

Answer: (D) All of these

Detailed Solution: All halogens form interhalogen compounds:

1. Types: AX, AX₃, AX₅, AX₇
2. Examples:
   • ClF, BrF, IF
   • ClF₃, BrF₃, IF₃
   • ClF₅, BrF₅, IF₅
   • IF₇

Key Concept: Interhalogen compounds

Difficulty Level: Easy

2015 Questions

Question 35: AIPMT 2015

Statement: Which of the following is used as a fire extinguisher?

Options: (A) CO₂ (B) SO₂ (C) NO₂ (D) ClO₂

Answer: (A) CO₂

Detailed Solution:

1. CO₂ fire extinguisher:
   • Heavier than air
   • Displaces oxygen
   • Does not conduct electricity
   • Suitable for electrical fires

Key Concept: Fire safety and extinguishing agents

Difficulty Level: Easy

Question 36: AIPMT 2015 Cancelled

Statement: The compound used as a germicide is:

Options: (A) I₂ (B) Cl₂ (C) Br₂ (D) F₂

Answer: (B) Cl₂

Detailed Solution:

1. Chlorine as germicide:

   • Strong oxidizing agent
   • Kills bacteria and microorganisms
   • Used in water purification

2. Reaction: Cl₂ + H₂O → HCl + HOCl (germicidal)

Key Concept: Disinfection and sterilization

Difficulty Level: Easy

2014 Questions

Question 37: AIPMT 2014

Statement: Which of the following has the highest bond angle?

Options: (A) H₂O (B) NH₃ (C) CH₄ (D) BF₃

Answer: (D) BF₃

Detailed Solution: Bond angles:

1. BF₃: 120° (trigonal planar)
2. CH₄: 109.5° (tetrahedral)
3. NH₃: 107° (trigonal pyramidal)
4. H₂O: 104.5° (bent)

Key Concept: Molecular geometry and bond angles

Difficulty Level: Easy

Question 38: AIPMT 2014

Statement: The element that forms maximum number of allotropes is:

Options: (A) C (B) P (C) S (D) Si

Answer: (A) C

Detailed Solution: Carbon allotropes:

1. 3D network: Diamond
2. 2D layers: Graphite, Graphene
3. 0D clusters: Fullerenes (C₆₀, C₇₀)
4. 1D tubes: Carbon nanotubes
5. Amorphous: Coal, charcoal

Maximum number of allotropes: Carbon

Key Concept: Allotropy

Difficulty Level: Medium

2013 Questions

Question 39: NEET 2013

Statement: Which of the following is used in the preparation of fertilizers?

Options: (A) HNO₃ (B) H₂SO₄ (C) H₃PO₄ (D) All of these

Answer: (D) All of these

Detailed Solution: Acids in fertilizer industry:

1. HNO₃: Ammonium nitrate (NH₄NO₃)
2. H₂SO₄: Ammonium sulfate ((NH₄)₂SO₄)
3. H₃PO₄: Superphosphate, triple superphosphate

Key Concept: Fertilizer industry

Difficulty Level: Easy

Question 40: NEET 2013

Statement: The compound used as a preservative in food is:

Options: (A) NaCl (B) NaNO₂ (C) NaNO₃ (D) Na₂SO₄

Answer: (B) NaNO₂

Detailed Solution: Sodium nitrite in food preservation:

1. Prevents: Botulism and bacterial growth
2. Applications: Cured meats, processed foods
3. Safety: Used in controlled amounts

Key Concept: Food chemistry and preservation

Difficulty Level: Easy

2012 Questions

Question 41: AIPMT 2012 Mains

Statement: Which of the following has highest melting point?

Options: (A) C (B) Si (C) Ge (D) Sn

Answer: (A) C

Detailed Solution: Melting points:

1. C (Diamond): 3550°C
2. Si: 1414°C
3. Ge: 938°C
4. Sn: 232°C

Trend: Decreases down Group 14 due to decreasing bond strength

Key Concept: Melting point trends

Difficulty Level: Easy

Question 42: AIPMT 2012 Prelims

Statement: The element used in the preparation of semiconductor is:

Options: (A) B (B) C (C) Si (D) P

Answer: (C) Si

Detailed Solution: Silicon semiconductors:

1. Properties: Tetravalent, covalent bonding
2. Applications: Computer chips, solar cells
3. Doping: Creates p-type and n-type semiconductors

Key Concept: Semiconductor materials

Difficulty Level: Easy

2011 Questions

Question 43: AIPMT 2011 Mains

Statement: Which of the following is used as a refrigerant?

Options: (A) NH₃ (B) SO₂ (C) CO₂ (D) All of these

Answer: (D) All of these

Detailed Solution: Refrigerants:

1. NH₃ (Ammonia): Traditional refrigerant
2. SO₂ (Sulfur dioxide): Industrial refrigeration
3. CO₂ (Carbon dioxide): Modern eco-friendly refrigerant

Key Concept: Refrigeration technology

Difficulty Level: Easy

Question 44: AIPMT 2011 Prelims

Statement: The compound used as a bleaching agent is:

Options: (A) H₂O₂ (B) Cl₂ (C) SO₂ (D) All of these

Answer: (D) All of these

Detailed Solution: Bleaching agents:

1. H₂O₂: Oxidizing bleaching agent
2. Cl₂: Forms HOCl (active bleaching agent)
3. SO₂: Reducing bleaching agent

Key Concept: Bleaching mechanisms

Difficulty Level: Easy

2010 Questions

Question 45: AIPMT 2010 Mains

Statement: Which of the following has highest density?

Options: (A) C (B) Si (C) Ge (D) Sn

Answer: (D) Sn

Detailed Solution: Densities of Group 14 elements:

1. C: 2.25 g/cm³
2. Si: 2.33 g/cm³
3. Ge: 5.32 g/cm³
4. Sn: 7.31 g/cm³ (highest)

Trend: Increases down the group due to increasing atomic mass

Key Concept: Density trends

Difficulty Level: Easy

Question 46: AIPMT 2010 Prelims

Statement: The element that forms polymeric structures is:

Options: (A) SiCl₄ (B) PCl₅ (C) SF₆ (D) None of these

Answer: (D) None of these

Detailed Solution: All mentioned compounds form discrete molecules:

1. SiCl₄: Tetrahedral molecules
2. PCl₅: Trigonal bipyramidal molecules
3. SF₆: Octahedral molecules

Polymeric p-block compounds: SO₃, P₄O₁₀, SiO₂

Key Concept: Molecular vs polymeric structures

Difficulty Level: Medium

2009 Questions

Question 47: AIPMT 2009

Statement: Which of the following is used in the preparation of matches?

Options: (A) P₄ (B) S₈ (C) C (D) Si

Answer: (A) P₄

Detailed Solution: Phosphorus in matches:

1. White phosphorus (P₄): Used in match heads
2. Red phosphorus: Used on striking surfaces
3. Safety matches: Separate red P and P₄S₃

Key Concept: Match chemistry

Difficulty Level: Easy

Question 48: AIPMT 2009

Statement: The compound used as a reducing agent is:

Options: (A) SO₂ (B) H₂SO₄ (C) HNO₃ (D) CO₂

Answer: (A) SO₂

Detailed Solution:

1. SO₂ (Sulfur dioxide):

   • Oxidation state +4
   • Can be oxidized to +6
   • Reaction: SO₂ + 2H₂S → 3S + 2H₂O

2. Others: Oxidizing agents or inert

Key Concept: Reducing agents

Difficulty Level: Easy

Topic-wise Analysis

1. Carbon Allotropes and Compounds (25% of questions)

Key Concepts:

• Allotropes: Diamond, graphite, fullerenes
• Hybridization: sp, sp², sp³
• Bonding and properties
• Industrial applications

Common Mistakes:

• Confusing allotrope properties
• Not knowing bond angles and structures
• Forgetting applications

2. Nitrogen Family Chemistry (20% of questions)

Key Concepts:

• Ammonia production and properties
• Nitrogen oxides and reactions
• Phosphorus allotropes
• Fertilizer chemistry

Common Mistakes:

• Not knowing oxidation states
• Confusing nitrogen oxides
• Forgetting industrial processes

3. Halogen Chemistry (18% of questions)

Key Concepts:

• Interhalogen compounds
• Halogen acids and properties
• Bleaching action
• Disinfection applications

Common Mistakes:

• Not knowing interhalogen formulas
• Confusing acid strengths
• Forgetting applications

4. Sulfur Compounds (15% of questions)

Key Concepts:

• Sulfur allotropes
• Sulfuric acid production
• Sulfur oxides
• Industrial applications

Common Mistakes:

• Not knowing allotropes
• Confusing SO₂ and SO₃
• Forgetting contact process

5. Boron and Aluminum Compounds (12% of questions)

Key Concepts:

• Boric acid and borax
• Aluminum extraction
• Amphoteric behavior
• Semiconductor applications

Common Mistakes:

• Not knowing amphoteric nature
• Confusing extraction methods
• Forgetting applications

6. Noble Gases (10% of questions)

Key Concepts:

• Properties and uses
• Compound formation
• Physical properties
• Applications

Common Mistakes:

• Not knowing uses
• Forgetting compound types
• Confusing properties

Year-wise Distribution

Concept Weightage Analysis

High Weightage Topics (30+ questions over 16 years):

1. Carbon Allotropes - Diamond, graphite, hybridization
2. Nitrogen Compounds - Ammonia, nitrogen oxides, fertilizers
3. Halogen Chemistry - Interhalogen compounds, bleaching
4. Sulfur Compounds - Allotropes, sulfuric acid

Medium Weightage Topics (15-30 questions):

1. Industrial Applications - Fertilizers, semiconductors
2. Oxidation States - Multiple oxidation state compounds
3. Molecular Geometry - VSEPR, bond angles

Low Weightage Topics (<15 questions):

1. Noble Gas Compounds - Limited compounds
2. Advanced Concepts - Band theory, semiconductors
3. Environmental Chemistry - Greenhouse gases

Success Rate by Topic

Preparation Strategy

Phase 1: Concept Building (2 weeks)

1. Master carbon chemistry

   • Allotropes and properties
   • Hybridization and bonding
   • Industrial applications

2. Study nitrogen family

   • Ammonia: Haber process, properties
   • Nitrogen oxides: Preparation, reactions
   • Phosphorus: Allotropes, compounds

3. Learn halogen chemistry

   • Interhalogen compounds
   • Halogen acids and strengths
   • Bleaching and disinfection

4. Understand sulfur chemistry

   • Allotropes and properties
   • Sulfuric acid: Contact process
   • Environmental impact

Phase 2: PYQ Practice (2 weeks)

1. Group-wise practice

   • Focus on high-weightage groups
   • Identify recurring patterns
   • Practice molecular geometry

2. Industrial applications

   • Learn processes systematically
   • Remember raw materials and products
   • Understand reaction conditions

3. Compound identification

   • Practice recognizing compounds
   • Learn uses and properties
   • Master formula writing

Phase 3: Revision (1 week)

1. Summary tables

   • Allotropes and properties
   • Industrial processes
   • Compound uses

2. Quick revision

   • Important reactions
   • Key concepts
   • Applications

Quick Reference Tables

Carbon Allotropes

Nitrogen Compounds

Halogen Interhalogen Compounds

Sulfur Allotropes

Industrial Processes

Practice Questions

Additional Practice (Not in PYQs)

1. Question: Which allotrope of carbon is used in pencils? Answer: Graphite

2. Question: The main component of natural gas is: Answer: CH₄ (methane)

3. Question: Which compound is called “King of Chemicals”? Answer: H₂SO₄ (sulfuric acid)

4. Question: The most abundant element in earth’s crust is: Answer: O (oxygen)

5. Question: Which gas is used in green houses? Answer: CO₂ (carbon dioxide)

Video Resources

Chapter Videos

1. Boron Family - Complete Study - 50 min
2. Carbon Family - Allotropes and Compounds - 60 min
3. Nitrogen Family - Comprehensive Coverage - 65 min
4. Oxygen Family - Sulfur Chemistry - 55 min
5. Halogens - Interhalogen and Applications - 50 min
6. Noble Gases - Properties and Compounds - 40 min
7. PYQ Solutions (2009-2024) - 120 min

📺 Access Complete Video Playlist

Final Tips for Exam

During Exam

1. Identify the group first (13-18)
2. Check the element and its properties
3. Consider the compound type (oxide, halide, etc.)
4. Apply relevant trends (periodic, group)
5. Think about applications if asked

Common Pitfalls to Avoid

1. Don’t confuse allotropes - learn structures
2. Don’t mix oxidation states - memorize common states
3. Don’t forget industrial processes - key reactions
4. Don’t ignore applications - frequently asked
5. Don’t rush geometry questions - draw structures

Summary

• Total Questions to Study: 48+ questions from 2009-2024
• Focus Areas: Carbon allotropes, nitrogen compounds, halogen chemistry, sulfur compounds
• Success Strategy: Master group properties, learn industrial processes, practice molecular geometry
• Time Allocation: 45-60 seconds per question in exam
• Target Score: Aim for 80% accuracy in this high-weightage chapter

This comprehensive coverage of P-Block Elements will help you master the most extensive chapter in Inorganic Chemistry and score maximum marks in NEET.

Compiled by SATHEE Team, IIT Kanpur | Last Updated: October 2024