Q.29 Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: Cymbopogon citratus is known as citronella grass which is a native of Sri Lanka.
Reason R: Citronella grass essential oil has significant amount of Citronellal and Geranoil content. besides
Geranial and Bomeol.
In the light of the above statements, choose the most appropriate answer from the options given below:
1. Both A and R are correct and R is the correct explanation of A
2. Both A and R are correct but R is NOT the correct explanation of A
3. A is correct but R is not correct
4. A is not correct but R is correct
Cymbopogon citratus (lemongrass) is native to Sri Lanka, making Assertion A correct, while Reason R correctly describes its essential oil composition but doesn’t explain the native origin claim.
The correct answer is option 2: Both A and R are correct but R is NOT the correct explanation of A.
Introduction
Cymbopogon citratus citronella grass Sri Lanka questions test NEET aspirants on botanical nomenclature, native distribution and essential oil chemistry. This assertion-reason format evaluates whether students distinguish between plant origin facts and chemical properties that don’t causally relate.
Assertion A Analysis: Native Origin
Cymbopogon citratus originates from Sri Lanka.
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Scientific name: Cymbopogon citratus (DC.) Stapf (Poaceae family)
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Common names: Citronella grass, West Indian lemongrass
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Native range: Sri Lanka (Ceylon) and surrounding South Asian/Maritime Southeast Asia regions
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Widely cultivated globally but Sri Lankan origin botanically established
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Distinguish from Cymbopogon nardus (true Sri Lankan citronella oil grass)
Verdict: Assertion A is CORRECT
Reason R Analysis: Essential Oil Composition
Citronella grass oil contains citronellal, geraniol, geranial, borneol.
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Major constituents: Citronellal (65-85%, key mosquito repellent)
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Geraniol (10-15%, rose-like aroma compound)
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Geranial (citral-a, lemon-like scent)
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Borneol (minor component, cooling effect)
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Used in perfumery, insect repellents, aromatherapy
Verdict: Reason R is CORRECT (composition accurately stated)
Relationship Analysis: Explanation Validity
Chemical composition doesn’t explain Sri Lankan nativity.
| Aspect | Assertion A | Reason R | Relationship |
|---|---|---|---|
| Content | Geographical origin | Chemical constituents | Independent facts |
| Causal link | Native distribution | Oil chemistry profile | No explanatory connection |
| Exam logic | Botanical taxonomy | Phytochemistry | Separate knowledge domains |
R provides supporting information about economic importance but doesn’t causally explain “why native to Sri Lanka”
Options Evaluation Table
| Option | A Status | R Status | Explanation? | Verdict |
|---|---|---|---|---|
| 1 | Correct | Correct | R explains A | ❌ Wrong |
| 2 | Correct | Correct | R doesn’t explain A | ✅ CORRECT |
| 3 | Correct | Incorrect | N/A | ❌ Wrong |
| 4 | Incorrect | Correct | N/A | ❌ Wrong |
Quick Memory Points for NEET
Cymbopogon Quick Facts:
C. citratus = Citronella grass = Sri Lanka native
Oil → Citronellal (65%) + Geraniol + Geranial + Borneol
C. nardus = True citronella oil (higher citronellal)
Exam Strategy for A-R Questions:
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Evaluate A independently → Native origin ✓
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Evaluate R independently → Oil composition ✓
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Check causal relationship → Chemistry ≠ Origin → Option 2
Common Exam Confusions Cleared
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C. citratus vs C. nardus: Citratus = Sri Lanka lemongrass; Nardus = Java citronella
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“Citronella grass” nomenclature: Refers to C. nardus commercially, but C. citratus botanically
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Native vs cultivated: Sri Lanka origin despite global cultivation
Definitive Answer: Option 2 confirms both statements true but independent facts.
