Some Basic Concepts of Chemistry NEET PYQs (1988–2026)

Solved Some Basic Concepts of Chemistry PYQs

3 recent questions with answers. The full set of 65 is free to practise.

1. NEET 2026HardMole Concept and Stoichiometry
   Q1

   The amount of carbon dioxide evolved upon complete combustion of $116\text{ g}$ of n-butane is (Given: atomic mass in amu H = 1, C = 12 and O = 16):

   • A352 g
   • B322 g
   • C176 g
   • D362 g

   Show answer & solution

   Correct answer: (A)

   n-butane: C₄H₁₀, molar mass = 4×12 + 10×1 = 58 g/mol.
   
   Moles of butane = 116/58 = 2 mol.
   
   Combustion: C₄H₁₀ + (13/2)O₂ → 4CO₂ + 5H₂O.
   
   2 mol butane gives 8 mol CO₂.
   
   Mass CO₂ = 8 × 44 = 352 g.
2. NEET 2026HardSignificant Figures
   Q2

   The numbers 17.0145 and 21.0235 were rounded to three figures after the decimal point. The resulting numbers, respectively, are:

   • A17.014 and 21.023
   • B17.015 and 21.023
   • C17.014 and 21.024
   • D17.015 and 21.024

   Show answer & solution

   Correct answer: (C)

   17.0145 rounded to 3 decimal places: 5th decimal is 5, 4th decimal is 4
   
   17.0145 → 17.014 (since 4 is even). 21.0235 → 21.024 (since 3 is odd, round up). So 17.014 and 21.024.
3. NEET 2025EasyAtomic Structure
   Q3

   Dalton's Atomic theory could not explain which of the following?

   • ALaw of multiple proportion
   • BLaw of gaseous volume
   • CLaw of gaseous volume
   • DLaw of constant proportion

   Show answer & solution

   Correct answer: (B)

   Dalton's theory could explain the laws of chemical combination. However, it could not explain the laws of gaseous volumes.

Topic-wise question count

Where NEET has asked from Some Basic Concepts of Chemistry, most frequent first.

• Mole Concept and Stoichiometry23
• Chemical Reactions and Equations16
• Gases and Gas Laws8
• Solution Chemistry6
• Atomic Structure4
• Empirical and Molecular Formula3
• Significant Figures2
• Chemical Composition1
• Redox Reactions1
• Hardness of Water1

Year-wise Some Basic Concepts of Chemistry questions in NEET

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