Top 5 NEET PYQ Patterns from OC-02

PYQ Pattern 1 (Highest Frequency): Anti-Markovnikov HX Specificity

• Typical question: "Anti-Markovnikov addition of HX to alkene with peroxide is possible with: (a) HCl (b) HBr (c) HI (d) Both HBr and HCl"
• Correct answer: (b) HBr only
• Frequency: Appears almost every year in some form
• Key phrase: "Peroxide = anti; only HBr — HCl too lazy, HI too crazy"

PYQ Pattern 2: Lindlar vs Na/$NH_{3}$ Geometry

• Typical question: "But-2-yne on treatment with Lindlar's catalyst gives: (a) cis-but-2-ene (b) trans-but-2-ene (c) butane (d) but-1-ene"
• Correct answer: (a) cis-but-2-ene
• Trap: Students swap the answers for the two reagents

PYQ Pattern 3: Ozonolysis Product Prediction

• Typical question: Given an alkene (or SMILES), predict carbonyl products after $O_{3}$/Zn/$H_{2}O$
• Method: Cleave C=C; add =O to each former C=C carbon; –CH= → CHO; –C(R)= → CO
• Example: 2-methylpropene → acetone + formaldehyde

PYQ Pattern 4: Butane Conformational Stability Order

• Typical question: Arrange anti, gauche, eclipsed, fully eclipsed in decreasing stability
• Correct: Anti > Gauche > Eclipsed > Fully eclipsed
• Trap: Placing gauche as least stable

PYQ Pattern 5: Alkyne Acidity and s-Character

• Typical question: Assertion-Reason about why terminal alkynes are more acidic
• Correct answer: 50% s-character → more electronegative C → more acidic H
• Second question type: "Which reacts with $NaNH_{2}$: alkyne/alkene/alkane?" → Terminal alkyne only

Exam Strategy for OC-02

1. Always check for the word "peroxide" before predicting HBr addition product.
2. Write out the Newman projection mentally for butane conformation questions.
3. For ozonolysis: work backwards — identify each C of C=C and what groups are on it.
4. For acidity: higher s-character → more acidic → can be deprotonated by $NaNH_{2}$.
5. For alkyne reduction: Lindlar's = L = cis; Na/$NH_{3}$ = N = trans.