Hydrocarbons NEET PYQs (1996–2026)

Solved Hydrocarbons PYQs

3 recent questions with answers. The full set of 88 is free to practise.

1. NEET 2022EasyAlkanes
   Q1

   The decreasing order of boiling points of the following alkanes is :
   (a) heptane
   (b) butane
   (c) 2-methylbutane
   (d) 2-methylpropane
   (e) hexane
   
   Choose the correct answer from the options given below :
   [NEET Re-2022]

   • A(a) $>$ (e) $>$ (c) $>$ (b) $>$ (d)
   • B(a) $>$ (c) $>$ (e) $>$ (d) $>$ (b)
   • C(c) $>$ (d) $>$ (a) $>$ (e) $>$ (b)
   • D(a) $>$ (e) $>$ (b) $>$ (c) $>$ (d)

   Show answer & solution

   Correct answer: (A)

   Solution
   Boiling point of alkanes $\alpha$ molar mass.
   Straight chain alkanes have more boiling pointthan branched alkanes.
   Heptane has high molar mass and2-methylpropane has low molar mass and is branched.
2. NEET 2022EasyAlkenes
   Q2

   The incorrect method for the synthesis of alkenes is : [NEET Re-2022]

   • Atreating vicinal dihalides with Zn metal
   • Btreatment of alkynes with Na in liquid NH 3
   • Cheating alkyl halides with alcoholic KOH
   • Dtreating alkyl halides in aqueous KOH solution

   Show answer & solution

   Correct answer: (D)

   (4) $R-Cl\to R-OH(3)$
3. NEET 2017ModerateAcidity and Stability
   Q3

   Which one is the correct order of acidity? (NEET 2017)

   • A$CH\equiv CH>{CH}_3-C\equiv CH>{CH}_2={CH}_2>{CH}_3-{CH}_3$
   • B$CH\equiv CH>{CH}_2={CH}_2>{CH}_3-C\equiv CH>{CH}_3-{CH}_3$
   • C${CH}_3-{CH}_3>{CH}_2={CH}_2>{CH}_3-C\equiv CH>CH\equiv CH$
   • D${CH}_2={CH}_2>{CH}_3-CH={CH}_2>{CH}_3-C\equiv CH>CH\equiv CH$

   Show answer & solution

   Correct answer: (A)

   Alkanes, alkenes and alkynes follow the following trend in their acidic behaviour:
   $$\stackrel{sp}{\mathrm{HC}}\equiv \stackrel{sp}{\mathrm{CH}}>\stackrel{{sp}^2}{H_{2}C}=\stackrel{{sp}^2}{{CH}_2}>\stackrel{{sp}^2}{{CH}_3}-\stackrel{{sp}^2}{{CH}_3}$$This is because sp -hybridised carbon is more electronegative than ${sp}^2$-hybridised carbon which is further more electronegative than ${sp}^3$ hybridised carbon. Hence, in ethyne proton can be released more easily than ethene and ethane.
   Among alkynes the order of acidity is :
   $$HC\equiv CH>{CH}_3-C\equiv CH>{CH}_3-C\equiv C-{CH}_3$$This is due to +I effect of $-{CH}_3$ group.

Topic-wise question count

Where NEET has asked from Hydrocarbons, most frequent first.

• Alkenes24
• Aromatic Hydrocarbons22
• Alkynes11
• Alkanes8
• Conformational Analysis6
• Reactions and Mechanisms5
• Isomerism in Hydrocarbons4
• Aromaticity and Huckel's Rule3
• Acidity and Stability2
• Alkanes/Alkenes/Alkynes2
• Ozonolysis and Polymerization1

Year-wise Hydrocarbons questions in NEET

Number of questions from this chapter in each year's paper(s).