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Chemistry

Some Basic Concepts of Chemistry

Mole concept, molar mass, laws of chemical combination, empirical and molecular formulas, stoichiometry, limiting reagent, and concentration terms such as molarity and molality make up this chapter. NEET tests it through numericals, mostly mole-to-particle conversions and limiting reagent problems.

Exam rules change between cycles. Confirm dates, syllabus and pattern against NTA's official site. We are not NTA.

Weightage: what the paper actually did

Some Basic Concepts of Chemistry carried 2 questions in the NEET 2026 paper. One paper is a data point, not a destiny: NTA moves weight between chapters every cycle, which is why the weightage tables deserve care. The stable facts are the paper's shape: 180 questions, 720 marks, +4 right, −1 wrong.

Sample PYQs from this chapter

Real questions NTA asked from Some Basic Concepts of Chemistry, with the answer and the working. Try before you peek.

Question 1 · NEET 2026

The number of hydrogen atoms present in 5.4 g of urea is: (Given: Molar mass of urea = 60 g mol−160\ \text{g mol}^{-1}; NA=6.022×1023 particles mol−1N_A = 6.022 \times 10^{23}\ \text{particles mol}^{-1})
  1. A.1.084×10231.084 \times 10^{23}
  2. B.1.084×10221.084 \times 10^{22}
  3. C.2.168×10222.168 \times 10^{22}
  4. D.2.168×10232.168 \times 10^{23}
Answer and explanation

Answer: D

Moles of urea = 5.4/60 = 0.09 mol. Urea, NH2CONH2NH_{2}CONH_{2}, contains 4 hydrogen atoms per molecule. So number of H atoms = 0.09 * 4 * 6.022 * 102310^{23} ≈\approx 2.168 * 102310^{23}. The distractors arise from using the wrong number of H atoms per molecule or a wrong power of ten. Why the other options are wrong: - (A) Wrong: uses 2 H atoms per molecule. - (B) Wrong: wrong power of ten. - (C) Wrong: wrong power of ten with 2 H atoms.

Question 2 · NEET 2026

When 1 dm3^3 of CO2CO_{2} gas is passed over hot coke, the volume of gaseous mixture after complete reaction at STP becomes 1.4 dm3^3. The composition of the gaseous mixture at STP is:
  1. A.0.8 dm3^3 of CO, 0.8 dm3^3 of CO2CO_{2}
  2. B.0.8 dm3^3 of CO, 0.6 dm3^3 of CO2CO_{2}
  3. C.0.6 dm3^3 of CO, 0.8 dm3^3 of CO2CO_{2}
  4. D.0.6 dm3^3 of CO, 0.4 dm3^3 of CO2CO_{2}
Answer and explanation

Answer: B

The reaction CO2+C(s)→2COCO_{2} + C(\text{s}) \rightarrow 2CO converts x dm3^3 of CO2CO_{2} into 2x dm3^3 of CO. Total final volume =(1−x)+2x=1+x=1.4=(1-x)+2x = 1+x = 1.4, so x = 0.4 dm3^3. Therefore CO2CO_{2} remaining =1−0.4=0.6=1-0.4=0.6 dm3^3 and CO formed =2×0.4=0.8=2\times0.4=0.8 dm3^3, which is option B.

How to practise Some Basic Concepts of Chemistry

Chapter by chapter, against real past-paper questions, on a screen: NEET is computer based from 2027. Read the chapter once, then attempt its PYQs until your accuracy stops climbing, and let the wrong answers tell you which lines to reread. If the chapter keeps refusing to stick, that has its own guide. There is also a free 12-question mock on the exam screen.

Nearby Chemistry chapters

Questions

How many questions did Some Basic Concepts of Chemistry have in NEET 2026?

Some Basic Concepts of Chemistry carried 2 questions in the NEET 2026 paper. Weightage shifts between cycles, so treat it as a probability, not a promise.

Where can I practise Some Basic Concepts of Chemistry PYQs for NEET?

In the BrainIt app, free until the 2027 exam: its bank holds 50,000 past NTA questions tagged to all 83 chapters, including this one, with accuracy tracked per chapter. Sample questions from this chapter are on this page.

Is Some Basic Concepts of Chemistry important for NEET 2027?

It is part of the Chemistry syllabus the paper draws from, and NEET 2027 is computer based, so practise it on a screen. Your own accuracy in the chapter matters more than any weightage table: a heavy chapter you already score well on needs less time than a light one you keep missing.

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