p-Block is the chapter students fear most in Inorganic Chemistry, because it looks like pure memorisation. It is not. Most NEET questions come from a small set of trends, structures and oxoacids that repeat year after year. This p block NEET PYQ analysis shows exactly which ones, so you can study a long chapter in a short, focused way.
For the overall plan, see our Inorganic Chemistry preparation plan. This article focuses on what past papers actually ask.
Want to test yourself first? Solve the p-Block Elements PYQs for free, then use this guide to fix the gaps.
Table of Contents
Why p-Block Is Worth the Effort
NEET usually asks two to three questions from p-Block. The NMC syllabus covers Groups 13 to 18, with most questions from Groups 15 to 18 in Class 12 NCERT. It remains in the syllabus, as our full Chemistry chapter list shows.
Shapes in this chapter come straight from VSEPR, so revise our Chemical Bonding PYQ patterns article first. For the exceptions that catch students, see our guide to Inorganic exceptions and trends.
p Block NEET PYQ Analysis: The Repeated Question Types
When you sort a decade of NEET chemistry PYQs from this chapter, five question types cover almost everything.
| Question type | Frequency | What it tests |
|---|---|---|
| Structures and shapes | Most frequent | Xenon fluorides, interhalogens, PCl₅, oxoacids |
| Oxoacids | Very frequent | Basicity, oxidation state, acid strength |
| Group trends | Very frequent | Bond enthalpy, electron gain enthalpy, hydride properties |
| Inert pair effect | Regular | Stable oxidation states down Groups 13–15 |
| Preparation and properties | Regular | NH₃, HNO₃, O₃, H₂SO₄, chlorine compounds |
For a quick warm-up before the full set, try these five quick p-Block practice questions.
Group Trends That Repeat
Hydrides of Group 15
| Property | Order |
|---|---|
| Thermal stability | NH₃ > PH₃ > AsH₃ > SbH₃ > BiH₃ |
| Basic strength | NH₃ > PH₃ > AsH₃ > SbH₃ > BiH₃ |
| Reducing character | BiH₃ > SbH₃ > AsH₃ > PH₃ > NH₃ |
| Boiling point | BiH₃ > SbH₃ > NH₃ > AsH₃ > PH₃ |
NH₃ has an unusually high boiling point because of hydrogen bonding.
Halogens (Group 17)
- Bond dissociation enthalpy: Cl₂ > Br₂ > F₂ > I₂. F₂ is low because of repulsion between lone pairs on the small fluorine atoms.
- Electron gain enthalpy is most negative for chlorine, not fluorine, for the same reason.
- Fluorine shows only the −1 oxidation state; the other halogens also show +1, +3, +5 and +7.
Inert pair effect: going down Groups 13 to 15, the lower oxidation state becomes more stable. So Tl⁺ is more stable than Tl³⁺, and Pb²⁺ is more stable than Pb⁴⁺. This is why Pb⁴⁺ compounds act as oxidising agents.
Oxoacids: Phosphorus, Sulphur and Chlorine
| Oxoacid | Basicity | Key fact |
|---|---|---|
| H₃PO₂ (hypophosphorous) | 1 | Two P–H bonds; strong reducing agent |
| H₃PO₃ (phosphorous) | 2 | One P–H bond; reducing agent |
| H₃PO₄ (orthophosphoric) | 3 | No P–H bond; not reducing |
| H₂SO₄ | 2 | Made by the Contact process with V₂O₅ catalyst |
Basicity rule: only the H atoms attached to oxygen (P–OH) are ionisable. H atoms bonded directly to phosphorus are not, but they make the acid reducing. This one rule answers almost every question on the oxoacids of phosphorus.
Acid strength of chlorine oxoacids: HClO₄ > HClO₃ > HClO₂ > HClO. More oxygen atoms spread the negative charge of the anion, making it more stable.
Structures and Shapes
| Molecule | Shape |
|---|---|
| XeF₂ | Linear |
| XeF₄ | Square planar |
| XeF₆ | Distorted octahedral |
| XeO₃ | Pyramidal |
| PCl₅ | Trigonal bipyramidal |
| ClF₃ | T-shaped |
| BrF₅ | Square pyramidal |
| SF₄ | See-saw |
| O₃ | Bent (angular) |
To get any shape, count bond pairs and lone pairs around the central atom and apply VSEPR. XeF₄, for example, has 4 bond pairs and 2 lone pairs, which gives a square planar shape.
Important Preparation and Property Facts
- Ammonia: Haber’s process, using an iron oxide catalyst with small amounts of K₂O and Al₂O₃.
- Nitric acid: Ostwald’s process, by catalytic oxidation of ammonia over platinum.
- White phosphorus is more reactive than red phosphorus because of angular strain in the P₄ molecule.
- Ozone is a strong oxidising agent and is diamagnetic.
- Noble gases: xenon forms the most compounds because it has the lowest ionisation enthalpy among the stable noble gases.
Worked PYQ-Pattern Questions
Q1. What is the shape of XeF₄?
Answer: Square planar. Xenon has 4 bond pairs and 2 lone pairs.
Q2. What is the basicity of H₃PO₃?
Answer: 2. Only two H atoms are attached to oxygen; the third is bonded to phosphorus.
Q3. Which is the strongest acid? (a) HClO (b) HClO₂ (c) HClO₃ (d) HClO₄
Answer: (d) HClO₄. Its anion is the most stabilised by charge spreading.
Q4. Which halogen has the highest bond dissociation enthalpy? (a) F₂ (b) Cl₂ (c) Br₂ (d) I₂
Answer: (b) Cl₂. F₂ is weakened by lone pair repulsion.
Q5. Which hydride of Group 15 is the strongest reducing agent?
Answer: BiH₃. Reducing character increases down the group as the M–H bond weakens.
Common Traps in This Chapter
- Saying fluorine has the most negative electron gain enthalpy
- Counting all H atoms in phosphorus oxoacids as ionisable
- Giving F₂ the highest bond enthalpy
- Calling XeF₄ tetrahedral
- Forgetting the inert pair effect when asked for stable oxidation states
Practise Every p-Block PYQ
This p block NEET PYQ analysis gives you the trends, oxoacids and shapes. Practice makes them automatic. Every previous year question from this chapter is available chapter-wise, free:
👉 Solve all p-Block Elements NEET PYQs
Keep one page with the shape table, the oxoacid table and the four hydride orders. Revise it once a week, and the chapter stops feeling long.
Conclusion
p-Block is long, but its questions are not random. Use this p block NEET PYQ analysis to master group trends, the inert pair effect, oxoacid basicity and VSEPR shapes. Then practise until each fact comes with its reason.
❓ FAQ
Q: How many questions come from p-Block in NEET? A: Usually two to three questions, which makes it one of the heaviest Inorganic chapters.
Q: Is p-Block in the NEET 2027 syllabus? A: Yes. The current NMC syllabus includes p-Block Elements, covering Groups 13 to 18.
Q: Which topic in p-Block is most important? A: Structures and shapes, especially of xenon fluorides and interhalogens, are asked most often, followed by oxoacids and group trends.
Q: How do I find the basicity of oxoacids of phosphorus? A: Count only the H atoms attached to oxygen atoms. H atoms bonded directly to phosphorus do not ionise.
Q: How should I revise p-Block for NEET? A: Use a p block NEET PYQ analysis to list the repeated facts, make one summary page of trends and shapes, and solve past questions chapter-wise.
Q: Where can I practise p-Block NEET PYQs for free? A: You can solve every previous year question from this chapter for free using the practice link in this article.