📋 Instructions for Candidates
- Each question carries 4 marks for correct answer
- -1 mark will be deducted for each incorrect answer
- No marks will be awarded or deducted for unattempted questions
- Mark your answers clearly in the answer sheet provided
- Use of calculator is not permitted
- Attempt all questions within the given time limit
Q.1
The molecular formula C₆H₁₂O₆ represents which of the following characteristics of organic compounds?
- Molecular formula only shows the ratio of atoms
- It gives complete structural information
- It shows the total number of each type of atom in one molecule
- It indicates the physical properties of the compound
Q.2
Which of the following statements about organic compounds is incorrect?
- They are primarily composed of carbon and hydrogen
- They can contain heteroatoms like N, O, S, P
- They always have low melting and boiling points
- They can exhibit isomerism
Q.3
The unique ability of carbon to form chains and rings is primarily due to:
- Small size and high electronegativity
- Tetravalency and catenation property
- Ability to form only single bonds
- High ionization energy
Q.4
Hybridization of carbon in CH₄, C₂H₄, and C₂H₂ respectively is:
- sp³, sp², sp
- sp, sp², sp³
- sp², sp³, sp
- sp³, sp, sp²
Q.5
The bond angles in methane (CH₄), ethene (C₂H₄), and ethyne (C₂H₂) are respectively:
- 109.5°, 120°, 180°
- 120°, 109.5°, 180°
- 180°, 120°, 109.5°
- 109.5°, 180°, 120°
Q.6
Which of the following represents a heterocyclic compound?
- Benzene
- Cyclohexane
- Pyridine
- Toluene
Q.7
The classification of organic compounds is based on:
- Functional groups only
- Carbon skeleton only
- Both functional groups and carbon skeleton
- Molecular weight only
Q.8
Vital force theory was disproved by the synthesis of:
- Methane
- Urea
- Ethane
- Benzene
Q.9
The IUPAC name of CH₃-CH(CH₃)-CH₂-CH₃ is:
- 2-methylbutane
- 3-methylbutane
- Isopentane
- 2-methylpentane
Q.10
The IUPAC name of (CH₃)₃C-CH₂-CH₃ is:
- 2,2-dimethylbutane
- 3,3-dimethylbutane
- tert-butylethane
- 2-methylpentane
Q.11
Which of the following represents the correct IUPAC name for CH₃-CH₂-CHBr-CH₃?
- 1-bromobutane
- 2-bromobutane
- 3-bromobutane
- 4-bromobutane
Q.12
The IUPAC name of CH₃-CH₂-CO-CH₃ is:
- Butanone
- 2-butanone
- Methyl ethyl ketone
- Both A and B
Q.13
The priority order of functional groups for IUPAC nomenclature is:
- -COOH > -CHO > -CO- > -OH
- -CHO > -COOH > -CO- > -OH
- -CO- > -COOH > -CHO > -OH
- -OH > -CO- > -CHO > -COOH
Q.14
The IUPAC name of CH₃-CH(OH)-CH₂-CHO is:
- 3-hydroxybutanal
- 2-hydroxybutanal
- 4-hydroxybutanal
- 1-hydroxybutanal
Q.15
In IUPAC nomenclature, the suffix for alkenes is:
Q.16
The IUPAC name of CH₃-CH₂-CH=CH₂ is:
- 1-butene
- 2-butene
- But-1-ene
- But-2-ene
Q.17
Compounds having the same molecular formula but different structures are called:
- Homologs
- Isomers
- Polymers
- Isotopes
Q.18
Chain isomerism is exhibited by:
Q.19
The total number of structural isomers possible for C₅H₁₂ is:
Q.20
Position isomerism is shown by:
- 1-propanol and 2-propanol
- Butane and isobutane
- Ethanol and dimethyl ether
- Propane and cyclopropane
Q.21
Functional isomerism is exhibited by:
- C₂H₅OH and CH₃-O-CH₃
- CH₃CHO and CH₃COCH₃
- Both A and B
- Neither A nor B
Q.22
Metamerism is shown by:
- Ethers
- Secondary amines
- Thioethers
- All of the above
Q.23
CH₃-CH₂-O-CH₂-CH₃ and CH₃-O-CH₂-CH₂-CH₃ are examples of:
- Chain isomerism
- Position isomerism
- Metamerism
- Functional isomerism
Q.24
Tautomerism is a special case of:
- Chain isomerism
- Functional isomerism
- Position isomerism
- Geometrical isomerism
Q.25
The phenomenon where a compound exists as a mixture of two rapidly interconverting isomers is called:
- Resonance
- Tautomerism
- Polymorphism
- Isomerism
Q.26
Which of the following methods is used to separate liquids with different boiling points?
- Crystallization
- Distillation
- Sublimation
- Extraction
Q.27
Fractional distillation is preferred over simple distillation when:
- Boiling points differ by more than 25°C
- Boiling points differ by less than 25°C
- Components are immiscible
- One component is volatile
Q.28
Steam distillation is used for:
- Water-soluble compounds
- Heat-sensitive compounds that are immiscible with water
- Ionic compounds
- High boiling point compounds only
Q.29
In column chromatography, the separation is based on:
- Differential adsorption
- Boiling point differences
- Solubility differences
- Density differences
Q.30
The stationary phase in paper chromatography is:
- Cellulose
- Silica gel
- Alumina
- Water absorbed on cellulose
Q.31
Rf value in thin layer chromatography is defined as:
- Distance traveled by solvent / Distance traveled by compound
- Distance traveled by compound / Distance traveled by solvent
- Distance traveled by compound × Distance traveled by solvent
- Distance traveled by compound + Distance traveled by solvent
Q.32
Which of the following is the most polar solvent?
- Hexane
- Chloroform
- Ethyl acetate
- Methanol
Q.33
Lassaigne's test is used to detect:
- Carbon and hydrogen only
- Nitrogen, sulfur, and halogens
- Oxygen only
- All elements in organic compounds
Q.34
In Lassaigne's test, sodium fusion extract gives a blood red color with FeCl₃ due to the presence of:
- Nitrogen
- Sulfur
- Both nitrogen and sulfur
- Halogens
Q.35
Silver nitrate test is used to detect:
- Nitrogen
- Sulfur
- Halogens
- Oxygen
Q.36
Fehling's test is positive for:
- All aldehydes
- All ketones
- Aliphatic aldehydes only
- Aromatic aldehydes only
Q.37
Benedict's test is used to detect:
- Reducing sugars
- Non-reducing sugars
- Aromatic aldehydes
- Ketones
Q.38
Lucas test is used to distinguish between:
- Primary, secondary, and tertiary alcohols
- Aldehydes and ketones
- Alkenes and alkynes
- Acids and bases
Q.39
Tollens' reagent gives a positive test with:
- All carbonyl compounds
- Aldehydes only
- Ketones only
- Both aldehydes and α-hydroxy ketones
Q.40
Iodoform test is positive for compounds containing:
- -CHO group
- -CO-CH₃ group or CH₃-CH(OH)- group
- -COOH group
- -NH₂ group
Q.41
In Dumas method for nitrogen estimation, nitrogen is converted to:
Q.42
In Kjeldahl's method, the organic compound is heated with:
- Concentrated HCl
- Concentrated H₂SO₄
- Concentrated HNO₃
- Aqua regia
Q.43
For estimation of carbon and hydrogen, the organic compound is combusted in the presence of:
- Nitrogen
- Oxygen
- Carbon dioxide
- Hydrogen
Q.44
In Carius method for sulfur estimation, sulfur is converted to:
Q.45
If 0.24 g of an organic compound on combustion gave 0.44 g of CO₂ and 0.18 g of H₂O, the percentage of carbon in the compound is:
(Atomic masses: C = 12, H = 1, O = 16)
📝 Answer Sheet
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Important Formulas for Reference:
Percentage of Carbon: % C = (12 × n × 100) / (44 × w) where n = mass of CO₂, w = mass of compound
Percentage of Hydrogen: % H = (2 × n × 100) / (18 × w) where n = mass of H₂O, w = mass of compound
Percentage of Nitrogen (Kjeldahl): % N = (1.4 × V × N) / W where V = volume of acid, N = normality, W = weight
Rf Value: Rf = Distance traveled by solute / Distance traveled by solvent front