NEET · Class 11 Chemistry
Some Basic Concepts of Chemistry MCQs for NEET
Every stoichiometry calculation in physical chemistry starts here, so mistakes in the mole concept quietly cost marks across the whole paper. Work through these questions, follow the working, then take a full 10-question test on the chapter in the app.
Take the free 10-question testPractice questions on Some Basic Concepts of Chemistry
Q1. The number of moles in 11.2 L of oxygen gas at STP is:
Q2. How many grams of NaOH are needed to make 500 mL of a 0.2 M solution? (Molar mass = 40 g/mol)
Q3. A compound contains 40% carbon, 6.7% hydrogen and 53.3% oxygen. Its empirical formula is:
Q4. In the reaction N₂ + 3H₂ → 2NH₃, 1 mole of N₂ reacts with 2 moles of H₂. The limiting reagent is:
Q5. The number of molecules in 4.4 g of CO₂ is about:
Quick NCERT recap
- 1 mole = 6.022 × 10²³ particles = gram molecular mass of the substance.
- 1 mole of any gas occupies 22.4 L at STP (273 K, 1 bar as per NCERT).
- Molarity M = moles of solute / litre of solution; it changes with temperature. Molality m = moles of solute / kg of solvent; it does not.
- Empirical formula gives the simplest ratio; molecular formula = n × empirical formula, where n = molecular mass / empirical formula mass.
- The limiting reagent is the reactant that runs out first and decides how much product forms.
- Significant figures: the answer carries as many significant figures as the least precise measurement used.
Exam tips for this chapter
- Convert everything to moles as step one — grams, litres and particles all become moles before anything else.
- For limiting reagent questions, divide moles of each reactant by its stoichiometric coefficient and pick the smallest.
- Keep molarity and molality apart: litres of solution versus kilograms of solvent.
- Numerical questions from this chapter are quick marks — do them first in the paper, not last.
Common questions
Is the mole concept asked directly in NEET?
Yes, usually one or two numerical questions, and the same skill is needed in solutions, equilibrium and electrochemistry.
Do I need a calculator for these questions?
No. NEET numericals from this chapter are designed to be done mentally or with simple arithmetic in about a minute.
Where can I take a full test on this chapter?
Open the free 10-question test in the app; your weak chapters return automatically on Day 1, 3, 8 and 20.