Stop Revising. Start Scoring.
Sections 1 to 13 taught you the chapter. This section finds out whether you can use it at NEET speed, which is a completely different skill. There is no new theory here — just 30 questions built to the NEET pattern (single-correct MCQs, plus the assertion-reason, match-the-column and statement-type formats NEET now uses freely), and a marking scheme that punishes the one thing students do most: guessing.
The rules of engagement
Key Point: Do not treat this as a reading exercise. Sit down with a blank sheet, a pen and a timer, and attempt all 30 questions in one unbroken sitting before you look at a single explanation.
| The setup | What it is |
|---|---|
| Number of questions | 30 |
| Marking scheme | correct, incorrect, unattempted |
| Maximum score | marks |
| Minimum possible score | marks |
| Suggested time limit | 30 minutes (NEET pace is about 1 minute per question) |
| Allowed | rough sheet, the atomic masses given in each question, your own brain |
| Not allowed | calculator, formula sheet, looking back at Sections 1 to 13 |
[NEET Important] One minute per question is not a suggestion; it is the whole game. NEET gives you a little over a minute for every question in the paper, and Chemistry is where toppers bank time for Biology and Physics. A question from this chapter should take 40 to 60 seconds. If one is eating two minutes, mark it, move on, and come back — that is exactly what you will have to do in the hall.
NEET's guessing maths
That is not decoration. Do the arithmetic once and you will never guess blindly again:
| What you do | Expected marks per question | Verdict |
|---|---|---|
| Blind guess among 4 options | Barely positive — and you burned a minute | |
| Eliminate 2, guess between the last 2 | Worth it | |
| Eliminate 3 (you basically know it) | Obviously | |
| Leave it blank | Better than a blind guess that costs you time |
[Exam Tip] The rule that comes out of that table: narrow first, then commit. Every question below has at least one option that is a "trap" built from a common mistake — a forgotten coefficient, a subscript ignored, molarity confused with molality. Learning to see the trap is what turns a blind guess into a two-option choice, and into .
What this set covers
| Topic | Questions | How many |
|---|---|---|
| SI units, prefixes and significant figures | Q1 to Q3 | 3 |
| Laws of chemical combination and Dalton's atomic theory | Q4 to Q7 | 4 |
| Atomic, molecular and formula mass; average atomic mass | Q8 to Q10 | 3 |
| Mole concept and Avogadro-number counting | Q11 to Q16 | 6 |
| Empirical and molecular formula; percentage composition | Q17 to Q19 | 3 |
| Stoichiometry and limiting reagent | Q20 to Q24 | 5 |
| Molarity, molality, mole fraction and dilution | Q25 to Q28 | 4 |
| Mixed (cross-topic) | Q29 and Q30 | 2 |
That spread is deliberate — it mirrors how NEET actually samples this chapter. The mole concept, stoichiometry and concentration terms together account for 15 of the 30 questions, because in the real paper they account for almost everything asked from Some Basic Concepts of Chemistry. Woven through the set are four assertion-reason questions, two match-the-column questions and two "which statement is correct/incorrect" questions, because NEET uses all three formats and each has its own way of tricking a student who reads too fast.
[NEET Important] For assertion-reason questions, decide the truth of A and R separately before you even think about whether R explains A. Most wrong answers on this format come from students who judged the pair as a whole.
Scoring Yourself Honestly
Mark your sheet with the real scheme — , , — and total it. Do not award yourself half marks for "I knew that one really". The number you get is the number that matters. And note the time you actually took: a 110 in 45 minutes and a 110 in 30 minutes are very different results in a NEET context.
The bands
| Your score (out of 120) | Verdict | What to do next |
|---|---|---|
| 104 to 120 | NEET ready. You are at 87% or above on a medium set, inside the time limit. | Move on. This chapter will not cost you marks. Revisit only the specific questions you missed, and re-time yourself once a month. |
| 80 to 103 | Good, but leaking marks. In NEET, "good" is not enough for Chemistry — toppers score near-full here. | These are almost always slips, not gaps: a subscript ignored, moles of molecules confused with moles of atoms, litres versus millilitres. Redo every wrong question without looking at the explanation first. |
| 52 to 79 | Shaky. The ideas are there; the speed and the execution are not. | For each wrong answer, go back to the section it came from (use the topic map above) and re-work its solved examples. Then re-attempt this set with the timer running. |
| Below 52 | Start again. | Work through Sections 1 to 9 properly, then Section 10's solved examples and Section 13's NEET Corner, then come back. Re-attempting this set now teaches you nothing. |
Read your own answer sheet: the three error piles
Before you touch the explanations, sort your mistakes into three piles. This is the most valuable ten minutes in the whole section.
- Concept errors — you did not know that Avogadro's law is about molecules rather than mass, or that molality uses the mass of solvent, not solution. Fixable by revision, and quickly: the topic map tells you exactly which section to reopen.
- Execution errors — right method, wrong arithmetic; you divided by the molar mass of instead of ; you forgot the 2 in ; you used 22.4 L when the question said 22.7 L. Fixable by slowing down for four seconds at the last step and by writing the unit next to every number.
- Reading errors — the question asked for the number of atoms and you gave the number of molecules; it asked which statement is incorrect and you picked the correct one; it asked for the mass of the product and you gave the mass of the limiting reagent. These are the cheapest marks in the paper to win back, and the ones students refuse to take seriously.
Key Point: A student who scores 84 with three concept errors is in far better shape than one who scores 84 with nine reading errors. The first has three things to learn. The second has a habit to break, and habits take longer.
[NEET Important] In NEET, the assertion-reason and statement-type questions are where reading errors pile up. If two or more of your mistakes are on Q5, Q7, Q14, Q23, Q29 or Q30, that is a format problem, not a chemistry problem — practise the format.
[Exam Tip] Every explanation below is written as a full step-by-step solution, so this set doubles as revision material. Read the explanation even for the questions you got right — sometimes you got there the slow way, and the fast way is what you will need in the exam hall.