Vitamins Classification

8 MCQs9-step worked example

Source: NCERT Unit 19PYQ coverage: NEET 2021, 2022, 2023, 2024, 2025Official key: NTA-verifiedLast reviewed: May 2026

Lesson

The trap that costs marks here: NEET regularly tests whether you can correctly sort vitamins into fat-soluble versus water-soluble groups, and whether you can link each vitamin to its specific deficiency disease. The common confusion is mixing up which vitamins are fat-soluble — students frequently misplace vitamin K into the water-soluble category, or swap the deficiency diseases between similar-sounding vitamins.

Fat-soluble vs water-soluble — the core classification.

Vitamins are classified based on their solubility. Fat-soluble vitamins — A, D, E, and K — dissolve in fats and organic solvents, are stored in liver and adipose tissue, and are not excreted easily. Water-soluble vitamins — the B-complex group (B₁, B₂, B₆, B₁₂, niacin, folic acid, biotin, pantothenic acid) and vitamin C — dissolve in water, are excreted in urine, and must be regularly replenished through diet (NCERT Class 12 Chemistry, Chapter 6 Part 2, page 22).

Key vitamin–deficiency pairs tested in NEET:

Vitamin A → Xerophthalmia (night blindness, dry eyes)
Vitamin D → Rickets (children), Osteomalacia (adults)
Vitamin E → Reproductive disorders, muscular dystrophy
Vitamin K → Delayed blood clotting, haemorrhage
Vitamin B₁ (Thiamine) → Beri-beri
Vitamin C (Ascorbic acid) → Scurvy
Vitamin B₁₂ → Pernicious anaemia
Niacin (B₃) → Pellagra
Folic acid → Megaloblastic anaemia

Watch out: The biomolecules bundle pattern in NEET (observed 2021–2025) frequently places a vitamin classification or deficiency question alongside carbohydrate/protein questions. The distractor strategy is swapped-class options — putting a B-complex vitamin among fat-soluble choices, or assigning scurvy to the wrong vitamin.

Practice MCQs

Select an option to see the explanation. Wrong answers show why your choice was tempting — and name the exact trap it exploits.

MCQ 1Easy RecallPractice

Which of the following is NOT a fat-soluble vitamin?

MCQ 2Easy RecallPractice

Deficiency of which vitamin causes scurvy?

MCQ 3Easy RecallPractice

Which vitamin deficiency leads to beri-beri?

MCQ 4Direct ApplicationPractice

A patient presents with delayed blood clotting after injury. The physician suspects a vitamin deficiency. Which vitamin is most likely deficient?

MCQ 5Direct ApplicationPractice

Fat-soluble vitamins are stored in the body and can accumulate to toxic levels (hypervitaminosis). Which group of vitamins carries this risk?

MCQ 6Direct ApplicationPractice

Pellagra is characterised by dermatitis, diarrhoea, and dementia. It is caused by deficiency of:

MCQ 7Concept TrapPractice

A student claims: "Since water-soluble vitamins are not stored, they cannot cause any harm even in large doses." Which of the following best addresses this claim?

MCQ 8Concept TrapPractice

Vitamins A and D are both fat-soluble, yet their deficiency diseases affect entirely different organ systems. Which pair correctly matches each vitamin to the primary system affected by its deficiency?

Worked Example

1
Given
Four statements linking vitamins to their solubility class or deficiency disease.
2
Required
Identify the single correct statement.
3
Concept
Vitamins are classified as fat-soluble (A, D, E, K) or water-soluble (B-complex, C). Each vitamin has a characteristic deficiency disease.
4
Formula
No numerical formula applies. This is a classification-and-recall problem.
5
Substitution
Evaluate each statement against known vitamin facts: - (i) Vitamin C → water-soluble, NOT fat-soluble. **Incorrect.** - (ii) Vitamin K → deficiency causes delayed clotting/haemorrhage, NOT rickets. Rickets is vitamin D deficiency. **Incorrect.** - (iii) Vitamin B₁ (thiamine) → deficiency causes beri-beri. **Correct.** - (iv) Vitamin D → fat-soluble, NOT water-soluble. **Incorrect.**
6
Calculation
No calculation needed. Direct comparison of each statement against established vitamin classification and deficiency data.
7
Final answer
Statement (iii) is correct — vitamin B₁ deficiency causes beri-beri.
8
Common trap
Statement (ii) exploits the K/D deficiency swap — students who vaguely recall "a fat-soluble vitamin causes rickets" may pick K instead of D. Statement (i) exploits the solubility confusion — vitamin C sounds like it could be stored because of its importance, but it is water-soluble and excreted.
9
Similar NEET-style question
"Which of the following pairs is correctly matched? (A) Vitamin A — Beri-beri (B) Vitamin D — Scurvy (C) Vitamin K — Blood clotting (D) Niacin — Night blindness" Answer: (C). Vitamin K is essential for blood clotting. The other three pairs are deliberately swapped. ---

Before solving, remember these

Key Fact

Vitamins

Organic compounds required in small amounts for metabolism, cannot be synthesized in body. Fat-soluble: A, D, E, K. Water-soluble: B-complex, C. Each prevents specific deficiency disease.

-- NCERT, p. 22

Formulas

DNA hydrogen bonds per base pair

A - T : 2; G - C : 3

Used to compute total H-bonds in a duplex of given GC%/AT% composition.

Symbol	Quantity	SI Unit
%GC	GC content	-

Valid when

Watson–Crick double helix

General formula of monosaccharides

C_{n} (H_{2} O)_{n}

Empirical formula of simple monosaccharides; glucose/fructose are C6H12O6.

Symbol	Quantity	SI Unit
n	carbon count	-

Valid when

Open-chain or cyclic forms of aldoses/ketoses

Peptide bonds in a polypeptide of N residues

# bonds = N - 1

Number of amide (peptide) bonds in a linear polypeptide of N amino acids.

Symbol	Quantity	SI Unit
N	residue count	-

Valid when

Linear (non-cyclic) polypeptide

Exam Traps & Common Mistakes

These are the exact patterns that cause wrong answers in NEET. Each trap includes when it triggers and how to avoid it.

Trap

DNA vs RNA base pairing

Category: Similar Terms

Student writes A=U for DNA or A=T for RNA. DNA: A=T, G≡C. RNA: A=U (no T), G≡C.

When it triggers

Question on base pairing or sugar identity.

How to avoid

DNA: deoxyribose, A-T-G-C bases. RNA: ribose, A-U-G-C bases (uracil instead of thymine). H-bond pairs: A=T (DNA) or A=U (RNA), G≡C (3 H-bonds, both).

Trap

Denaturation does NOT break primary structure

Category: Similar Terms

Student claims denaturation breaks peptide bonds. Denaturation only breaks H-bonds, ionic, hydrophobic interactions; primary structure (peptide bonds) intact.

When it triggers

Question about protein denaturation effects.

How to avoid

Denaturation: heat/pH/organic solvents disrupt secondary, tertiary, quaternary structure. Primary structure (covalent peptide bonds) requires hydrolysis to break.

Mistake

Claims denaturation breaks peptide bonds (primary structure).

Root cause: concept gap

Correction

Denaturation breaks H-bonds, ionic, hydrophobic; preserves peptide bonds. Hydrolysis (acid/base/enzyme) breaks primary structure.

Mistake

Writes A=U for DNA or A=T for RNA.

Root cause: concept gap

Correction

DNA: deoxyribose, A=T, G≡C. RNA: ribose, A=U (no T), G≡C.

Past Year Questions

6 questions from NEET 2021, 2022, 2023, 2024, 2025. Answers verified against NTA official keys.

NEET 2025

Match List-I with List-II. List-I List-II (Name of Vitamin) (Deficiency disease) A. Vitamin B I. Cheilosis 12 B. Vitamin D II. Convulsions C. Vitamin B III. Rickets 2 D. Vitamin B IV. Pernicious anaemia 6 Choose the correct answer from the options given below:

1A-IV, B-III, C-II, D-I

2A-I, B-III, C-II, D-IV

3A-IV, B-III, C-I, D-II

4A-II, B-III, C-I, D-IV

NTA Answer: Option 3(final)

NEET 2025

Given below are two statements : Statement-I : Benzenediazonium salt is prepared by the reaction of aniline with nitrous acid at 273 – 278 K. It decomposes easily in the dry state. Statement-II : Insertion of iodine into the benzene ring is difficult and hence iodobenzene is prepared through the reaction of benzenediazonium salt with KI. In the light of the above statements, choose the most appropriate answer from the options given below :

1Statement I is incorrect but Statement II is correct

2Both Statement I and Statement II are correct

3Both Statement I and Statement II are incorrect

4Statement I is correct but Statement II is incorrect

NTA Answer: Option 2(final)

NEET 2024Revised key

Match List I with List II. List I List II (Reaction) (Reagents/Condition) A. I. B. II. CrO 3 C. III. KMnO /KOH,  4 D. IV. (i) O 3 (ii) Zn-H O 2 Choose the correct answer from the options given below:

1A-IV, B-I, C-III, D-II

2A-III, B-I, C-II, D-IV

3A-IV, B-I, C-II, D-III

4A-I, B-IV, C-II, D-III

NTA Answer: Option 3(revised_final)

NEET 2023

Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R : Assertion A : A reaction can have zero activation energy. Reasons R : The minimum extra amount of energy absorbed by reactant molecules so that their energy becomes equal to threshold value, is called activation energy. In the light of the above statements, choose the correct answer from the options given below :

1Both A and R are true and R is NOT the correct explanation of A

2A is true but R is false

3A is false but R is true

4Both A and R are true and R is the correct explanation of A

NTA Answer: Option 3(final)

NEET 2022

The incorrect statement regarding enzymes is

1Enzymes are very specific for a particular reaction and substrate.

2Enzymes are biocatalysts.

3Like chemical catalysts enzymes reduce the activation energy of bio processes.

4Enzymes are polysaccharides.

NTA Answer: Option 4(final)

NEET 2021

An organic compound contains 78% (by wt.) carbon and remaining percentage of hydrogen. The right option for the empirical formula of this compound is : [Atomic wt. of C is 12, H is 1]

1CH

2CH 4

3CH

4CH 2 3

NTA Answer: Option 4(final)

How NEET usually asks this

Recurring question shapes from past papers. Each pattern shows why wrong options look tempting.

Biomolecules — recall and classify carbohydrates, proteins, nucleic acids, vitamins; identify base pairs and peptide bonds.

RecallMedium

Common distractors

swapped classes

Tempts surface-level recall.

Test yourself on this topic with real past-paper questions:

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