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🔥🌟 MDCAT/ECAT/FSC/XII Grand Chemistry MCQs Interactive Quiz # 8 🧪💡 | Learn & Practice!
1. The internal angle in cyclopropane is
Correct:
The bond angle in cyclopropane is 60°, deviates significantly from the optimal angle of 109.5°, so it has very high angle strains.
The sp³-sp³ orbitals can only overlap partially because of the angle deviation, so the overlapping is not as effective as it should be, and as a result, the C-C bond in cyclopropane is relatively weak.
The bond angle in cyclopropane is 60°, deviates significantly from the optimal angle of 109.5°, so it has very high angle strains.
The sp³-sp³ orbitals can only overlap partially because of the angle deviation, so the overlapping is not as effective as it should be, and as a result, the C-C bond in cyclopropane is relatively weak.
2. In Bucky balls the smallest molecule known contains ………..carbon atoms
Correct:
In Bucky balls the smallest molecule known contains 60 carbon atoms.
In Bucky balls the smallest molecule known contains 60 carbon atoms.
3. The condensation polymerization of terephthalic acid (a dicarboxylic acid) with ethylene glycol (a diol) give
Correct:
The condensation polymerization of terephthalic acid (a dicarboxylic acid) with ethylene glycol (a diol) give polyethylene terephthalate (PET), which is a common type of polyester used in various application including textiles as synthetic fibers (like polyester), packaging and beverage containers.
The condensation polymerization of terephthalic acid (a dicarboxylic acid) with ethylene glycol (a diol) give polyethylene terephthalate (PET), which is a common type of polyester used in various application including textiles as synthetic fibers (like polyester), packaging and beverage containers.
4. The nuisance of knocking can be reduced by the process
Correct:
Reforming (Isomerisation) is the process of conversion of hydrocarbons (gasoline) with low octane ratings into those with higher octane ratings that can be used as a fuel in internal combustion engine.
It is the conversion of straight alkanes into branched chain alkanes in order to increase the octane number of a fuel to avoid knocking.
The process of reforming is carried out under high pressure and temperature using platinum catalyst.
Reforming (Isomerisation) is the process of conversion of hydrocarbons (gasoline) with low octane ratings into those with higher octane ratings that can be used as a fuel in internal combustion engine.
It is the conversion of straight alkanes into branched chain alkanes in order to increase the octane number of a fuel to avoid knocking.
The process of reforming is carried out under high pressure and temperature using platinum catalyst.
5. Which of the following pairs of compounds represents isomerism?
Correct:
Structural isomers have same molecular formula but different structural formulae.
Alcohols and ethers are functional group isomers.
Only Option (c) shows isomerism because dimethyl ether and ethanol share the same molecular formula (C₂H₆O) but differ in structure due to different functional groups (functional isomerism).
Structural isomers have same molecular formula but different structural formulae.
Alcohols and ethers are functional group isomers.
Only Option (c) shows isomerism because dimethyl ether and ethanol share the same molecular formula (C₂H₆O) but differ in structure due to different functional groups (functional isomerism).
6. The number of five membered and six membered rings in C60 Bucky ball are respectively
Correct:
In Bucky balls, the carbon atoms are bonded together in twenty hexagons and twelve pentagons which are arranged like the panels on some soccer balls.
🔎 Details
🔥C₆₀ Buckminsterfullerene (Buckyball) is a spherical molecule made of 60 carbon atoms.
🔥Its structure resembles a soccer ball: a truncated icosahedron.
🔥This polyhedron is composed of:
➡️12 pentagons (five membered rings)
➡️20 hexagons (six membered rings)
🔥Together, these polygons form the closed cage structure of C₆₀.
🔥A truncated icosahedron =
➡️ Take a 20 triangle solid (icosahedron)
➡️ Chop off the corners
➡️ You get 12 pentagons + 20 hexagons
➡️ Looks exactly like a soccer ball or the C₆₀ buckyball.
In Bucky balls, the carbon atoms are bonded together in twenty hexagons and twelve pentagons which are arranged like the panels on some soccer balls.
🔎 Details
🔥C₆₀ Buckminsterfullerene (Buckyball) is a spherical molecule made of 60 carbon atoms.
🔥Its structure resembles a soccer ball: a truncated icosahedron.
🔥This polyhedron is composed of:
➡️12 pentagons (five membered rings)
➡️20 hexagons (six membered rings)
🔥Together, these polygons form the closed cage structure of C₆₀.
🔥A truncated icosahedron =
➡️ Take a 20 triangle solid (icosahedron)
➡️ Chop off the corners
➡️ You get 12 pentagons + 20 hexagons
➡️ Looks exactly like a soccer ball or the C₆₀ buckyball.
7. Which of the following has the highest nucleophilicity?
Correct:
🔎 A nucleophile is a chemical species that donates an electron pair to an electrophile to form a chemical bond
🔎 Nucleophilicity = the ability of a species to donate an electron pair and attack an electrophile (usually a carbon atom).
🔎 It depends on charge, electronegativity, size, and solvation.
🔎 Electronegativity – “greed for electrons” – is the opposite of nucleophilicity – “giving away electrons.
🔎 So less the electronegativity more the nucleophilicity of ion.
👉 Among the given options, CH₃⁻ has the highest nucleophilicity because the negative charge is on carbon, which is less electronegative and less solvated, making it highly reactive toward electrophiles.
➡️ Nucleophilicity decreases as CH₃⁻ > NH₂⁻> OH⁻ > F⁻
🔥Acids form conjugate base after donation of proton. In acids, strong acid forms weak conjugate base while weak acid forms strong conjugate base. Order of basic strength (nucleophilicity)
➡️ 👉 CH₃⁻ > NH₂⁻> OH⁻ > F⁻
🔥The acidic character of hydrides in a period of periodic table increases on moving from left to right side. Hence, their acids have the following order of acidic strength
➡️ CH₄ > NH₃ > H₂O > HF.
🔎 A nucleophile is a chemical species that donates an electron pair to an electrophile to form a chemical bond
🔎 Nucleophilicity = the ability of a species to donate an electron pair and attack an electrophile (usually a carbon atom).
🔎 It depends on charge, electronegativity, size, and solvation.
🔎 Electronegativity – “greed for electrons” – is the opposite of nucleophilicity – “giving away electrons.
🔎 So less the electronegativity more the nucleophilicity of ion.
👉 Among the given options, CH₃⁻ has the highest nucleophilicity because the negative charge is on carbon, which is less electronegative and less solvated, making it highly reactive toward electrophiles.
➡️ Nucleophilicity decreases as CH₃⁻ > NH₂⁻> OH⁻ > F⁻
🔥Acids form conjugate base after donation of proton. In acids, strong acid forms weak conjugate base while weak acid forms strong conjugate base. Order of basic strength (nucleophilicity)
➡️ 👉 CH₃⁻ > NH₂⁻> OH⁻ > F⁻
🔥The acidic character of hydrides in a period of periodic table increases on moving from left to right side. Hence, their acids have the following order of acidic strength
➡️ CH₄ > NH₃ > H₂O > HF.
8. Homologous series have ……….. chemical characteristics, ………. general methods of preparation, ………… structural features and functional group.
Correct:
🔎 Homologous series have
➡️ Same chemical characteristics
➡️ Same general methods of preparation
➡️ Same structural features and functional group.
🔎 Homologous series have
➡️ Same chemical characteristics
➡️ Same general methods of preparation
➡️ Same structural features and functional group.
9. Which group elements form nitrides with general formula M₃N₄?
Correct:
🔥 Group IVA have oxidation state +4, so they form M⁴⁺ ions.
🔥 Nitrogen forms the nitride ion N³⁻.
To balance charges: 3(M⁴⁺) + 4(N³⁻) → M₃N₄ 👈 (The LCM of 3 and 4 = 12)
👉🏼So, group IVA elements form nitrides of the type M₃N₄
🔥 Group IVA have oxidation state +4, so they form M⁴⁺ ions.
🔥 Nitrogen forms the nitride ion N³⁻.
To balance charges: 3(M⁴⁺) + 4(N³⁻) → M₃N₄ 👈 (The LCM of 3 and 4 = 12)
👉🏼So, group IVA elements form nitrides of the type M₃N₄
10. Which group elements form superoxides with general formula MO₂?
Correct:
Superoxides contain the ion O₂²⁻.
These are typically formed by larger alkali metals (K, Rb, Cs) of group IA because their larger cations can stabilize the large superoxide anion.
K, Rb, Cs → form superoxides (MO₂) because of their larger cation size, which stabilizes the large O₂²⁻ ion
Superoxides contain the ion O₂²⁻.
These are typically formed by larger alkali metals (K, Rb, Cs) of group IA because their larger cations can stabilize the large superoxide anion.
K, Rb, Cs → form superoxides (MO₂) because of their larger cation size, which stabilizes the large O₂²⁻ ion
11. Which of the following gas is evolved when phosphorus reacts with water?
Correct:
In group VA, phosphorus reacts vigorously with water to produce phosphoric acid and phosphine.
This reaction of phosphorus with water is an auto-redox reaction in which phosphorus is both oxidized and reduced into phosphoric acid (P with +5 oxidation state) and phosphine (P with -3 oxidation state) respectively.
Phosphorus does not react significantly with cold or hot water under normal conditions. However, white phosphorus can react with hot concentrated alkali to produce phosphine (PH₃), but with pure water the reaction is negligible.
In group VA, phosphorus reacts vigorously with water to produce phosphoric acid and phosphine.
This reaction of phosphorus with water is an auto-redox reaction in which phosphorus is both oxidized and reduced into phosphoric acid (P with +5 oxidation state) and phosphine (P with -3 oxidation state) respectively.
Phosphorus does not react significantly with cold or hot water under normal conditions. However, white phosphorus can react with hot concentrated alkali to produce phosphine (PH₃), but with pure water the reaction is negligible.
12. Alkali metals reacts with alcohols liberating hydrogen gas along with
Correct:
🔎 Alkali metals react vigorously with alcohols to form metal alkoxide (Ethoxide) with the evolution of hydrogen gas.
This is in fact a displacement reaction in which alkali metal being more reactive displaced hydrogen from alcohol as hydrogen gas along with the formation of respective alkali metal alkoxide (like ethoxide) salt.
Alkaline earth metals have a very limited reactivity with alcohols.
2M(s) + 2C₂H₅OH(aq) → 2C₂H₅OM(aq) + H₂(g) [M = Li, Na, K etc.]
🔎 Alkali metals react vigorously with alcohols to form metal alkoxide (Ethoxide) with the evolution of hydrogen gas.
This is in fact a displacement reaction in which alkali metal being more reactive displaced hydrogen from alcohol as hydrogen gas along with the formation of respective alkali metal alkoxide (like ethoxide) salt.
Alkaline earth metals have a very limited reactivity with alcohols.
2M(s) + 2C₂H₅OH(aq) → 2C₂H₅OM(aq) + H₂(g) [M = Li, Na, K etc.]
13. The IUPAC name of CH₃COOCH(CH₃)₂ is
Correct:
🔎 The compound is CH₃COOCH(CH₃)₂. The –COO– part shows it is an ester.
The part before –COO– (CH₃CO–) comes from ethanoic acid (acetic acid; CH₃COOH).
The alkoxy part after –O– (CH(CH₃)₂) is isopropyl group comes from isopropyl alcohol (CH(CH₃)₂OH).
So, the ester is named officially as:
Alkyl group from alcohol: isopropyl
Acid-derived part: ethanoate
👉 Final Name → isopropyl ethanoate ✅
(b) Ethyl propanoate → Ethyl group ≠ isopropyl; acid part is propanoate, not ethanoate ❌
(c) isopropyl acetate → Common name, not IUPAC (though it refers to the same compound) ❌
(d) Propyl ethanoate → Propyl group ≠ isopropyl. ❌
🔎 The compound is CH₃COOCH(CH₃)₂. The –COO– part shows it is an ester.
The part before –COO– (CH₃CO–) comes from ethanoic acid (acetic acid; CH₃COOH).
The alkoxy part after –O– (CH(CH₃)₂) is isopropyl group comes from isopropyl alcohol (CH(CH₃)₂OH).
So, the ester is named officially as:
Alkyl group from alcohol: isopropyl
Acid-derived part: ethanoate
👉 Final Name → isopropyl ethanoate ✅
(b) Ethyl propanoate → Ethyl group ≠ isopropyl; acid part is propanoate, not ethanoate ❌
(c) isopropyl acetate → Common name, not IUPAC (though it refers to the same compound) ❌
(d) Propyl ethanoate → Propyl group ≠ isopropyl. ❌
14. The derived name of CH₂=CH–CH₂–CO–CH₃ is
Correct:
🔎 The general derived name of ketone is alkyl alkyl ketone for unsymmetrical ketone (both alkyl groups are placed alphabetically).
🔎 For symmetrical ketone, the name is dialkyl ketone.
🔎 The structure CH₂=CH–CH₂–CO–CH₃ contains:
✨ an allyl group → CH₂=CH–CH₂–
✨ a methyl ketone group → –CO–CH₃
👉 So its derived (common) name is allyl methyl ketone.
🔎 The molecule may be called vinyl acetone because it is acetone (CH₃–CO–CH₃) with a vinyl substituent (–CH=CH₂) replacing one methyl group.
🔎 The general derived name of ketone is alkyl alkyl ketone for unsymmetrical ketone (both alkyl groups are placed alphabetically).
🔎 For symmetrical ketone, the name is dialkyl ketone.
🔎 The structure CH₂=CH–CH₂–CO–CH₃ contains:
✨ an allyl group → CH₂=CH–CH₂–
✨ a methyl ketone group → –CO–CH₃
👉 So its derived (common) name is allyl methyl ketone.
🔎 The molecule may be called vinyl acetone because it is acetone (CH₃–CO–CH₃) with a vinyl substituent (–CH=CH₂) replacing one methyl group.
15. Propanoyl chloride is a member of
Correct:
🔎 ✅ Propanoyl chloride is a member of the acid halides family.
✨Propanoyl chloride has the formula CH₃–CH₂–COCl. It is derived from propanoic acid (CH₃–CH₂–COOH) by replacing the –OH group of the carboxyl with a –Cl atom.
✨ Compounds of the type R–COCl are called acid chlorides (or acyl chlorides), which belong to the family of acid halides. 👈
🔎 ✅ Propanoyl chloride is a member of the acid halides family.
✨Propanoyl chloride has the formula CH₃–CH₂–COCl. It is derived from propanoic acid (CH₃–CH₂–COOH) by replacing the –OH group of the carboxyl with a –Cl atom.
✨ Compounds of the type R–COCl are called acid chlorides (or acyl chlorides), which belong to the family of acid halides. 👈
16. Select the correct IUPAC name of neopentane.
Correct:
🔥 Neopentane (C₅H₁₂) is a branched alkane [(CH₃)₄C] has a central carbon bonded to four methyl groups (a “tetramethylmethane” core).
The longest chain is propane (3 carbon atoms), with two methyl substituents on the second carbon making its IUPAC Name 2,2-dimethylpropane.
The correct IUPAC name of neopentane is 2, 2-dimethylpropane. 👈
🔥 Neopentane (C₅H₁₂) is a branched alkane [(CH₃)₄C] has a central carbon bonded to four methyl groups (a “tetramethylmethane” core).
The longest chain is propane (3 carbon atoms), with two methyl substituents on the second carbon making its IUPAC Name 2,2-dimethylpropane.
The correct IUPAC name of neopentane is 2, 2-dimethylpropane. 👈
17. What is the order of priority of following functional groups?
−OH, −NH₂, −COOH, −CHO, −COR
−OH, −NH₂, −COOH, −CHO, −COR
Correct:
🔥 The order priority of the functional groups in the IUPAC system of nomenclature is
Carboxylic Acid > Sulfonic Acid > Esters > Acid Halides > Amides > Cyanides > Aldehyde > Ketones > Alcohols > Amines > Alkynes > Alkenes > Alkanes.👈
🔥 The order priority of the functional groups in the IUPAC system of nomenclature is
Carboxylic Acid > Sulfonic Acid > Esters > Acid Halides > Amides > Cyanides > Aldehyde > Ketones > Alcohols > Amines > Alkynes > Alkenes > Alkanes.👈
18. The chemical formula Chile saltpeter is
Correct:
🔎 Chile saltpeter or Chilean saltpeter is a natural mineral source of sodium nitrate, NaNO₃👈.
It is called so because large deposits were found in Chile. 👈
KNO₃ → Potassium nitrate → common saltpeter, not Chilean saltpeter.
AgNO₃ → Silver nitrate → unrelated
🔎 Chile saltpeter or Chilean saltpeter is a natural mineral source of sodium nitrate, NaNO₃👈.
It is called so because large deposits were found in Chile. 👈
KNO₃ → Potassium nitrate → common saltpeter, not Chilean saltpeter.
AgNO₃ → Silver nitrate → unrelated
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