intro
MCQs 1:
Which alcohol exhibits the least reactivity upon cleavage of the O-H bond?
Topic: Reactivity of Alcohols
Correct Answer: A) Tertiary Alcohols
- Reactivity of alcohols is determined by the stability of the carbocation formed when the O-H bond breaks.
- Among the given options, tertiary alcohols form the most stable carbocations due to the presence of three alkyl groups that can donate electrons.
- Therefore, tertiary alcohols are the least reactive as they are the most stable, leading us to answer A, "Tertiary alcohols".
MCQs 2:
In the IUPAC system of nomenclature, what is the purpose of the numerical prefix written before the name of an alcohol?
Topic: IUPAC Nomenclature of Alcohols
Correct Answer: D) To mark the position(s) of the hydroxyl (-OH) group on the parent chain
- The numerical prefix in the name of an alcohol in the IUPAC nomenclature system is used to indicate the position(s) of the hydroxyl (-OH) group.
- This is consistent with other naming conventions in IUPAC nomenclature, where locants are used to specify the location of functional groups.
- Consequently, the correct choice is D, "To mark the position(s) of the hydroxyl (-OH) group on the parent chain."
MCQs 3:
Which substance is commonly referred to as a universal solvent due to its dissolving capacity?
Topic: Solvent Properties of Water
Correct Answer: A) H2O
- The term "universal solvent" refers to a substance capable of dissolving a wide range of other substances. Water (H2O), due to its polar nature, is able to dissolve a large number of compounds.
- While other options, like CH3OH and C2H5OH, do have solvent properties, they are not as universally effective as water.
- This leads us to the correct answer, A: "H2O".
MCQs 4:
What is the standard molecular formula for aliphatic alcohols (where R represents an alkyl group)?
Topic: Molecular Structure of Aliphatic Alcohols
Correct Answer: B) R - OH
- Aliphatic alcohols are characterized by the presence of a hydroxyl (-OH) group attached to an alkyl group (R). This distinguishes them from other organic compounds such as aldehydes (R - CHO) or carboxylic acids (R - COOH).
- Therefore, the standard formula for an aliphatic alcohol is "R - OH".
- Hence, the correct answer is B, "R - OH".
MCQs 5:
A particular type of methyl phenol is commonly referred to as which of the following?
Topic: Nomenclature of Alcohol Derivatives
Correct Answer: A) Cresol
- The term methyl phenol pertains to an organic compound where a methyl group is directly bound to the phenol molecule.
- Out of the provided options, cresol meets this definition. Benzyl alcohol, on the other hand, has the methyl group attached to a benzene ring through an -CH2OH group, not directly to the phenol.
- Therefore, the correct answer is A, "Cresol".
MCQs 6:
The compound 2, 4, 6 Trinitrophenol is primarily utilized commercially under which name?
Topic: Commercial Names of Organic Compounds
Correct Answer: B) Picric acid
- The compound 2, 4, 6 Trinitrophenol has three nitro groups (-NO2) attached to a phenol molecule, making it a very potent compound.
- Commercially, this compound is known as picric acid, not to be confused with TNT (Trinitrotoluene), which is a different nitro compound.
- As a result, the correct answer is B, "Picric acid".
MCQs 7:
Why are phenols more acidic than alcohols?
Topic: Acidic Nature of Phenols
Correct Answer: C) The phenoxide ion is stabilized due to resonance.
- Phenols are more acidic than alcohols because when phenol loses a proton (H+), it forms a phenoxide ion, which is stabilized by resonance.
- This resonance stabilization is not available in alkoxide ions (formed when alcohols lose a proton), making phenols more acidic.
- Hence, the correct answer is C, "The phenoxide ion is stabilized due to resonance."
Question 8:
How does the acidic strength compare among primary, secondary, and tertiary alcohols?
Topic: Acidic Strength of Alcohols
Correct Answer: A) 1° > 2° > 3°
- The acidity of alcohols is determined by the ease of releasing protons. Alkyl groups are electron-donating, which means they increase the electron density on the oxygen atom, decreasing the polarity of the O-H bond.
- Therefore, the more alkyl groups present, the less likely the molecule is to release protons, leading to lower acidity.
- Consequently, the correct answer is A, "1° > 2° > 3°".
Question 9:
When the O-H bond in the hydroxyl group of an alcohol is broken, how does the alcohol react?
Topic: Reactivity of Alcohols
Correct Answer: A) As a nucleophile
- Alcohols can act as either nucleophiles or electrophiles, depending on which bond is broken. If the O-H bond is broken, a nucleophilic reaction occurs.
- In this case, a carbocation is formed, making the alcohol act as a nucleophile.
- Therefore, the correct response is A, "As a nucleophile".
Question 10:
What is the common designation of the most simple hydroxy derivative of benzene?
Topic: Nomenclature of Hydroxy Derivatives of Benzene
Correct Answer: A) Phenol
- The simplest hydroxyl derivative of benzene is referred to as phenol. This is both its common and IUPAC name.
- Other options, such as cresol, cyclohexanol, and glycerol, represent more complex derivatives or different classes of compounds altogether.
- As a result, the correct answer is A, "Phenol".
Question 11:
Which order correctly represents the reactivity of alcohols when the C-O bond is disrupted?
Topic: Reactivity of Alcohols
Correct Answer: D) Tertiary alcohol > Secondary alcohol > Primary alcohol
- The reactivity of alcohols when the C-O bond is broken depends on the surface area available for a nucleophile to strike.
- Tertiary alcohols have more surface area for a nucleophile to attack than primary alcohols.
- Consequently, the correct answer is D, "Tertiary alcohol > Secondary alcohol > Primary alcohol".
Question 12:
Which of the following methods can successfully produce alcohols?
Topic: Synthesis of Alcohols
Correct Answer: B) Hydration of alkenes
- Alcohols can be derived from several processes, including the hydration of alkenes and the reaction of Grignard reagents with aldehydes or ketones.
- Hydrogenation of alkanes and alkynes does not directly lead to the formation of alcohols.
- Thus, the correct answer is B, "Hydration of alkenes".
Question 13:
What substance is used to denature ethanol?
Topic: Denaturing of Ethanol
Correct Answer: A) Methanol
- Ethanol is denatured, or made unfit for consumption, by adding methanol. This process creates a product known as methylated spirit.
- Small amounts of other substances, such as pyridine or acetone, may also be used to denature ethanol.
- Therefore, the correct response is A, "Methanol".
Question 15:
What is another name for methanol?
Topic: Nomenclature of Alcohols
Correct Answer: A) Wood spirit
- Methanol can be referred to by several names, depending on its use or context.
- In a historical context where it was produced through the destructive distillation of wood, it is often referred to as "wood spirit".
- As a consequence, the correct response is A, "Wood spirit".
Question 16:
Which of the following substances has a dissociation constant (Ka) value of 1.3×10^-10?
Topic: Acidity Constants of Substances
Correct Answer: D) Phenol
- The dissociation constant, or Ka, is an indicator of the strength of an acid. A lower Ka value implies a weaker acid.
- Among the given options, phenol has a Ka value of 1.3×10^-10, indicating it is a relatively weak acid compared to others.
- Therefore, the correct response is D, "Phenol".
Question 17:
Which compound from the list below contains an aryl carbon?
Topic: Aryl Carbon in Compounds
Correct Answer: D) Phenol
- An aryl carbon refers to the sp2 hybridized carbon of an aromatic ring that is linked to a hydroxyl group.
- Among the listed compounds, only phenol exhibits this characteristic, with its OH group directly connected to an aryl carbon.
- Therefore, the correct response is D, "Phenol".
Question 18:
Which alcohol from the following is the most reactive towards an esterification reaction?
Topic: Alcohol Reactivity in Esterification
Correct Answer: A) CH3OH
- The presence of larger groups reduces the reactivity of alcohols and carboxylic acids in esterification due to the effect of steric hindrance.
- Consequently, tertiary alcohols are the least reactive, and methanol (CH3OH), being the simplest alcohol, is the most reactive.
- Thus, the correct response is A, "CH3OH".
Question 19:
What is the correct IUPAC name for the following compound?
Topic: IUPAC Nomenclature in Organic Chemistry
Correct Answer: B) But-3-en-2-ol
- When determining the IUPAC name for a compound, the hydroxyl group takes precedence over the double bond, influencing the numbering of the carbon atoms.
- In this case, the hydroxyl group is on the second carbon, and the double bond is on the third carbon. Thus, the correct name should be "But-3-en-2-ol".
- Consequently, the correct response is B, "But-3-en-2-ol".
Question 20:
Which of the following carbonyl compounds is reduced to secondary alcohols by LiAlH4?
Topic: Reduction of Carbonyl Compounds
Correct Answer: B) Ketone
- LiAlH4 is a powerfully reducing agent that can convert carbonyl compounds into alcohols.
- However, when considering the options, ketones specifically react with this reducing agent to be transformed into secondary alcohols. A common example would be the reduction of acetone to isopropyl alcohol.
- This leads us to the correct response, B, "Ketone".
Question 21:
With which of the following are ethers functionally isomeric?
Topic: Functional Isomerism in Organic Compounds
Correct Answer: B) Alcohols
- Functional group isomers are compounds with the same molecular formula but different functional groups.
- In the given options, ethers and alcohols are functional group isomers as they share the same molecular formula but differ in their functional groups.
- Therefore, the correct response is B, "Alcohols".
Question 22:
Which of the following is recognized as lactic acid?
Topic: Organic Compound Nomenclature
Correct Answer: B) 2-Hydroxy propanoic acid
- Different organic compounds are often associated with common names that differ from their systematic IUPAC names.
- With respect to the options provided, 2-Hydroxy propanoic acid is commonly referred to as lactic acid.
- This brings us to the correct response, B, "2-Hydroxy propanoic acid".
Question 23:
Which of the following is more accurate about water compared to alcohol?
Topic: Acid-Base Characteristics of Water and Alcohol
Correct Answer: D) Superior proton donor
- The comparison of water and alcohol's acid-base characteristics can be illustrated through their reactions with alkoxides.
- In such a reaction, water proves to be a superior proton donor, making it a stronger acid compared to alcohol.
- Thus, the correct response is D, "Superior proton donor".
Question 24:
What is the accurate order of reactivity for alcohols in reactions that involve the cleavage of the C-O bond?
Topic: Reactivity Order in Alcohol Cleavage
Correct Answer: B) 3o > 2o > 1o
- The reactivity order of alcohols in reactions involving C-O bond cleavage is influenced by the electron-releasing nature of alkyl groups.
- These groups enhance electron density towards oxygen, making the C-O bond more polar and easier to cleave.
- Therefore, the correct response is B, "3o > 2o > 1o".
Question 25:
The process of alcohol oxidation involves the cleavage of which bonds?
Topic: Bond Cleavage in Alcohol Oxidation
Correct Answer: C) Both O-H and C-H
- The transition from alcohol to the oxidized state involves an intricate process requiring the cleavage of specific bonds.
- In this scenario, both the O-H and the C-H bonds are cleaved during the oxidation process.
- Hence, the correct response is C, "Both O-H and C-H".