NEET ChemistryUpdated 19 Oct 2026

General Organic Chemistry (Revision) and Isomerism: NEET PYQs and weightage

General Organic Chemistry (Revision) and Isomerism carries 2.0 of 100 Chemistry marks in NEET by past-paper share: 14 of the 707 tagged NEET Chemistry PYQs in the ViJEEta bank (NEET 2013–2026). It ranks 25 of 26 Chemistry chapters.

Take the 25-question General Organic Chemistry (Revision) and Isomerism test Formula sheet ↓All NEET Chemistry chapters

2.0/100 Weight in Chemistry

Exam importance (2/5, by past-paper share)

14 NEET PYQs

244 Practice questions

197 With measured difficulty

How the weight is computed: this chapter's tagged NEET PYQs divided by all tagged NEET Chemistry PYQs in the bank (14 of 707), times 100, with repeated questions counted once. The bank does not store the year of each NEET question, so none is printed. Computed from the bank at build time. Updated 19 Oct 2026.

General Organic Chemistry (Revision) and Isomerism: formula sheet for NEET

14 formulas, each with when to use it. Copy it onto one page of your notebook: that page is this chapter's handbook.

Kjeldahl %N
$% N = \frac{1.4 \times M \times 2 ( V - \frac{V _{1}}{2} )}{m}$
Use it when: $N H_{3}$ from $m$ g of compound is absorbed in $V$ mL of $M$ $H_{2} S O_{4}$ and the leftover acid takes $V_{1}$ mL of $M$ $NaOH$
Dumas %N
$% N = \frac{28 \times V _{0} \times 100}{22400 \times m}$
Use it when: $N_{2}$ gas is collected and $V_{0}$ is its volume in mL at STP (22400 mL, not 22.4)
Dumas STP correction
$V_{0} = \frac{p _{1} \times V \times 273}{760 \times T}$
$p_{1} = P_{atm} - aqueous tension$
Use it when: $N_{2}$ is collected over $KOH (aq)$ at $T$ K, and the pressure is given in mm Hg
Carius %halogen
$% X = \frac{atomic mass of X}{molar mass of AgX} \times \frac{m _{1}}{m} \times 100$
Use it when: $m$ g of compound gives $m_{1}$ g of $AgX$ (for $AgBr$ , $\frac{80}{188}$ )
Carius %S
$% S = \frac{32}{233} \times \frac{m _{1}}{m} \times 100$
Use it when: sulphur is weighed as $m_{1}$ g of $BaS O_{4}$
%C
$% C = \frac{12}{44} \times \frac{m _{2}}{m} \times 100$
Use it when: combustion of $m$ g gives $m_{2}$ g of $C O_{2}$ (absorbed in $KOH$ )
%H
$% H = \frac{2}{18} \times \frac{m _{1}}{m} \times 100$
Use it when: combustion of $m$ g gives $m_{1}$ g of $H_{2} O$ (absorbed in anhydrous $CaC l_{2}$ )
Combustion
$C_{x} H_{y} + (x + \frac{y}{4}) O_{2} \to x C O_{2} + \frac{y}{2} H_{2} O$
Use it when: you need the moles of $C O_{2}$ and $H_{2} O$ from a hydrocarbon
Retardation factor
$R_{f} = \frac{distance moved by the substance}{distance moved by the solvent} (both measured from the base line)$
Use it when: reading a TLC or paper chromatogram ( $R_{f}$ is always below 1)
%P (phosphomolybdate)
$% P = \frac{31}{1877} \times \frac{m _{1}}{m} \times 100$
Use it when: P is weighed as $m_{1}$ g of $(N H_{4})_{3} P O_{4} \cdot 12Mo O_{3}$
%P (pyrophosphate)
$% P = \frac{62}{222} \times \frac{m _{1}}{m} \times 100$
Use it when: P is weighed as $m_{1}$ g of $M g_{2} P_{2} O_{7}$ (2 P atoms, so 62)
%O
$% O = \frac{32}{88} \times \frac{m _{1}}{m} \times 100$
$% O = 100 - (sum of all other %)$
Use it when: O is converted to $CO$ and then to $C O_{2}$ ( $m_{1}$ g) over $I_{2} O_{5}$ ; otherwise find it by difference
Steam distillation
$p = p_{1} + p_{2} (organic + water = atmospheric)$
Use it when: explaining why a steam-volatile liquid distils below its own b.p. (the mixture boils just below 373 K)
Carbocation stability
$(C H_{3})_{3} C^{+} > (C H_{3})_{2} C H^{+} > C H_{3} C H_{2}^{+} > C H_{3}^{+}$
Use it when: ranking cations by hyperconjugation (tert-butyl has 9 C–H bonds, $C H_{3}^{+}$ has none that can overlap)

Trap

In Kjeldahl, H₂SO₄ is dibasic, so the NaOH volume must be halved (V − V₁/2) and the result doubled. Kjeldahl also fails for nitro, azo and ring nitrogen (pyridine), so use Dumas for those.

How does NEET ask General Organic Chemistry (Revision) and Isomerism?

3 real previous-year questions from this chapter, as printed in the paper, each with its worked solution. Answer the first one here with no sign-in.

Q1ChemistryNEET UG PYQRevision of Projections

Try right here · No sign-in

The right option for the statement “Tyndall effect is exhibited by” is:

Answer key (A) & worked solution

Correct answer: Option A

Starch is a colloid and thus shows Tyndall effect. Rest all forms true solution.

Q2ChemistryNEET UG PYQMiscellaneous Examples

Match items of Column I with the items of Column II and assign the correct code : Column IColumn II(A)Cyanide process(i)Ultrapure Ge(B)Froth floatation process(ii)Dressing of ZnS(C)Electrolytic reduction(iii)Extraction of Al(D)Zone refining(iv)Extraction of Au(v)Purification of Ni

AA – (iii); (B) – (iv); (C) – (v); (D) – (i)

BA – (iv); (B) – (ii); (C) – (iii); (D) – (i)

CA – (ii); (B) – (iii); (C) – (i); (D) – (v)

DA – (i); (B) – (ii); (C) – (iii); (D) – (iv)

Answer key (B) & worked solution

Correct answer: Option B

Cyanide process → Leaching process of Au

A u + a q . 2 N a C N \to [A u (C N)_{2}]^{-} + N a^{+}

Froth floatation process → Dressing of ZnS (It is applicable for concentration of sulphide ores) Electrolytic reduction → Extraction of Al Zone refining → Purification of Si, Ge

Q3ChemistryNEET UG PYQGeometrical Isomerism of Cyclic Compounds

Which one of the following compounds can exist as cis-trans isomers?

A1,1-Dimethylcyclopropane

B1,2-Dimethylcyclohexane

CPent-1-ene

D2-Methylhex-2-ene

Answer key (B) & worked solution

Correct answer: Option B

1,2-Dimethylcyclohexane

Which topics in General Organic Chemistry (Revision) and Isomerism carry the most questions?

The 12 busiest of 16 topics, by tagged PYQs, then practice questions. Counted from the bank. Updated 19 Oct 2026.

Topic	PYQs	Practice questions
Tautomerism	5	23
Geometrical Isomerism of Cyclic Compounds	3	55
Optical Active Compounds	2	56
Aromaticity	2	3
Revision of Projections	1	3
Miscellaneous Examples	1	0
Chirality	0	27
Relationship Between Optical Isomers	0	17
Number of Optical Isomers	0	15
Absolute and Relative Nomenclature	0	12
E and Z Isomerism	0	11
Cahn, Ingold, and Prelog Rules	0	10

Why does General Organic Chemistry (Revision) and Isomerism show "–" until you answer 3 questions?

Unknown is not zero. Until you answer at least 3 graded questions in General Organic Chemistry (Revision) and Isomerism, ViJEEta shows – instead of a zero or a 50% default. Book exercises can raise chapter mastery up to 0.60, adaptive practice up to 0.75, and only a timed chapter test or mock can certify 0.80 and above.

How ViJEEta scores you

What happens when you test General Organic Chemistry (Revision) and Isomerism?

Every chapter test is 25 questions. It starts at moderate difficulty and adapts after each saved answer. If you open a solution before answering, that attempt earns no credit, so your mastery stays honest.

Start the General Organic Chemistry (Revision) and Isomerism test

Chapters either side of General Organic Chemistry (Revision) and Isomerism by weight

Haloalkanes and Haloarenes Weight 2.4/100 Gasesous State* Weight 2.1/100 Carboxylic Acids and Derivatives Weight 1.1/100

General Organic Chemistry (Revision) and Isomerism: NEET PYQs and weightage

General Organic Chemistry (Revision) and Isomerism: formula sheet for NEET

Kjeldahl %N

Dumas %N

Dumas STP correction

Carius %halogen

Carius %S

%C

%H

Combustion

Retardation factor

%P (phosphomolybdate)

%P (pyrophosphate)

%O

Steam distillation

Carbocation stability

How does NEET ask General Organic Chemistry (Revision) and Isomerism?

Which topics in General Organic Chemistry (Revision) and Isomerism carry the most questions?

Why does General Organic Chemistry (Revision) and Isomerism show "–" until you answer 3 questions?

What happens when you test General Organic Chemistry (Revision) and Isomerism?

Chapters either side of General Organic Chemistry (Revision) and Isomerism by weight