intro
MCQs 1:
What is the classification of the acid when the –COOH group is directly attached to a benzene ring?
Topic: Organic Chemistry - Functional Groups and Classification
Correct Answer: D) Aromatic
- When the carboxyl group (-COOH) is directly bonded to a benzene ring, the acid is classified as an "aromatic" acid.
- An example of such an acid is benzoic acid. The presence of the benzene ring in the structure qualifies it as a member of the aromatic group.
MCQs 2:
What substance is used to prepare alkane nitriles (R-CN) from alkyl halides?
Topic: Organic Chemistry - Preparation of Alkane Nitriles
Correct Answer: D) Alcoholic Potassium cyanide
- Alkane nitriles can be synthesized from alkyl halides using alcoholic potassium cyanide.
- The alkyl halide is treated with alcoholic potassium cyanide in a process known as nucleophilic substitution, resulting in the formation of alkane nitriles.
MCQs 3:
What is the product formed when a carboxylic acid reacts with ammonia and is then heated?
Topic: Organic Chemistry - Reaction of Carboxylic Acid
Correct Answer: C) Acid amides
- When carboxylic acids react with ammonia, they initially form ammonium salts.
- Upon heating, these salts undergo dehydration to produce acid amides.
MCQs 4:
By reacting Grignard’s reagent with which of the following can carboxylic acid be prepared?
Topic: Organic Chemistry - Grignard Reagent and its Reactions
Correct Answer: B) CO2
- Grignard's reagent, when reacted with carbon dioxide (CO2), forms a carboxylic acid.
- The reaction proceeds through an intermediate stage, which after acid hydrolysis, gives the final product, carboxylic acid.
MCQs 5:
What is the reducing agent that transforms carboxylic acids into alkanes?
Topic: Organic Chemistry - Reduction of Carboxylic Acids
Correct Answer: C) HI and red P
- Carboxylic acids can be converted to alkanes through the process of reduction.
- The reducing agents used in this conversion are HI and red P (red phosphorus).
MCQs 6:
What type of reaction is characterized by the formation of an ester from acetic acid in the presence of acid and ethanol?
Topic: Organic Chemistry - Esterification
Correct Answer: B) Nucleophilic substitution reaction
- The formation of an ester from acetic acid and ethanol, in the presence of an acid, is an example of a Nucleophilic substitution reaction.
- During the process, the nucleophile (ethanol) substitutes a group in the electrophile (acetic acid) to form the ester.
MCQs 7:
What is the product formed when carboxylic acids react with lithium aluminum hydride?
Topic: Organic Chemistry - Reduction of Carboxylic Acids
Correct Answer: C) Alcohols
- Carboxylic acids can be partially reduced to alcohols when reacted with lithium aluminum hydride.
- The reduction process involves the loss of the oxygen atom from the carboxyl group and the gain of a hydrogen atom to form the alcohol.
Question 8:
What is the result when alkenes are subjected to heat in the presence of alkaline KMnO4?
Topic: Organic Chemistry - Oxidation of Alkenes
Correct Answer: D) Formation of Carboxylic acids
- Alkenes undergo oxidation when heated with alkaline KMnO4, a strong oxidizing agent.
- The double bonds of the alkenes are cleaved during the reaction, leading to the formation of carboxylic acids.
Question 9:
When esters form from the reaction of carboxylic acids and alcohols, which group is displaced?
Topic: Organic Chemistry - Esterification Process
Correct Answer: B) -OH
- The formation of esters involves a reaction between carboxylic acids and alcohols, known as esterification.
- In this reaction, the -OH group from the carboxylic acid is replaced by an alkyl group from the alcohol.
Question 10:
What is the common feature between Phthalic acid and Malonic acid?
Topic: Organic Chemistry - Classification of Carboxylic Acids
Correct Answer: B) They are Dicarboxylic
- Phthalic acid and Malonic acid share a common characteristic: both are classified as dicarboxylic acids.
- This classification is because both acids contain two carboxyl (-COOH) functional groups in their molecular structure.
Question 11:
What is the correct IUPAC nomenclature for the compound commonly known as formic acid?
Topic: Organic Chemistry - Nomenclature of Carboxylic Acids
Correct Answer: A) Methanoic acid
- Formic acid is the common name for a carboxylic acid that contains a single carbon atom.
- According to IUPAC nomenclature, a carboxylic acid with one carbon atom is named Methanoic acid.
Question 12:
What is the trend of solubility of carboxylic acids in water as the molecular mass increases?
Topic: Organic Chemistry - Solubility Trends of Carboxylic Acids
Correct Answer: B) Decreases
- The solubility of carboxylic acids in water is primarily due to hydrogen bonding.
- As the molecular mass of carboxylic acids increases, solubility decreases because hydrogen bonding becomes less effective when compared to the increasing van der Waals forces.
Question 13:
Which two functional groups combine to form the carboxylic group?
Topic: Organic Chemistry - Formation of Carboxylic Acids
Correct Answer: C) Carbonyl and Hydroxyl
- A carboxylic group is characterized by the presence of a carbonyl and a hydroxyl functional group.
- The carbonyl group (C=O) and the hydroxyl group (-OH) combine to form a carboxylic group (-COOH).
Question 14:
Which one of the following is the strongest acid?
Topic: Organic Chemistry - Acidity of Carboxylic Acids
Correct Answer: B) HCOOH
- The strength of a carboxylic acid is determined by the stability of its corresponding carboxylate ion.
- Formic acid (HCOOH) is a stronger acid because it is a smaller molecule with less electron-donating alkyl groups, resulting in a more stable carboxylate ion.
Question 15:
What is the product formed when carboxylic acids are dehydrated strongly in the presence of phosphorus pentoxide?
Topic: Organic Chemistry - Dehydration of Carboxylic Acids
Correct Answer: D) Acetic anhydride
- A strong dehydrating agent like phosphorus pentoxide (P2O5) is used to remove water from carboxylic acids.
- The resulting compound is an anhydride, specifically acetic anhydride in this case.
Question 16:
If organic compounds X and Y can both react with sodium metal to release hydrogen gas and their reaction together produces an organic compound Z with a fruity smell, what could X, Y, and Z be?
Topic: Organic Chemistry - Reaction of Alcohols with Carboxylic Acids
Correct Answer: A) X = Alcohol, Y = Acetic acid, Z = Ester
- Both alcohols and carboxylic acids can react with sodium metal to produce hydrogen gas.
- The reaction between an alcohol and a carboxylic acid leads to the formation of an ester, which is known for its fruity smell.
Question 17:
What gas is released when carboxylic acids interact with active metals resulting in salt formation?
Topic: Organic Chemistry - Reaction of Carboxylic Acids with Active Metals
Correct Answer: D) H2
- Carboxylic acids can react with active metals, such as sodium.
- These reactions typically result in the formation of salts and the release of Hydrogen gas.
Question 18:
What is the IUPAC name of the compound CH3 ‒ CO ‒ NH2?
Topic: Organic Chemistry - Nomenclature of Organic Compounds
Correct Answer: C) Acetamide
- The compound CH3 ‒ CO ‒ NH2 is an Amide.
- According to IUPAC nomenclature, it's named as Acetamide.
Question 19:
What compound is produced when Carboxylic acids are heated with alcohols in the presence of concentrated H2SO4?
Topic: Organic Chemistry - Esterification
Correct Answer: D) Esters
- The reaction between carboxylic acids and alcohols in the presence of an acid catalyst, such as concentrated H2SO4, is known as Esterification.
- This reaction results in the formation of esters, a class of compounds that are often characterized by their fruity smells.
Question 20:
In the given chemical reaction, which substance(s) act as a catalyst?
Topic: Organic Chemistry - Catalysts in Chemical Reactions
Correct Answer: D) Both Potassium dichromate and Sulphuric acid
- A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process.
- In this particular reaction, both Potassium dichromate and Sulphuric acid act as catalysts.
Question 21:
How does the reactivity of carboxylic acids compare to that of mineral acids?
Topic: Organic Chemistry - Reactivity of Carboxylic Acids
Correct Answer: A) Less reactive
- Reactivity refers to the readiness of a molecule to undergo a chemical reaction.
- Even though both carboxylic and mineral acids are acidic, carboxylic acids are generally less reactive. This can be determined by comparing the pH of a common carboxylic acid (acetic acid, pH ~2.4) to a typical mineral acid (hydrochloric acid, pH ~1).
Question 22:
What alcohol turns into acetic acid upon oxidation with K2Cr2O7 and dilute H2SO4?
Topic: Organic Chemistry - Oxidation of Alcohols
Correct Answer: B) Ethanol
- Oxidation is a type of chemical reaction that involves the loss of electrons.
- In this case, ethanol (C2H5OH) undergoes oxidation in the presence of the oxidizing agent K2Cr2O7 and acid H2SO4. The process transforms ethanol into acetic acid (CH3COOH).
Question 23:
What gas is produced when carbonates and bicarbonates undergo decomposition in the presence of carboxylic acids?
Topic: Organic Chemistry - Decomposition of Carbonates and Bicarbonates by Carboxylic Acids
Correct Answer: D) Carbon dioxide
- Decomposition is a type of chemical reaction where a compound breaks down into two or more simpler substances.
- When carboxylic acids come into contact with carbonates and bicarbonates, the reaction results in the release of carbon dioxide gas. For instance, when acetic acid (CH3COOH) reacts with sodium carbonate (Na2CO3), the products are sodium acetate (CH3COONa), carbon dioxide (CO2), and water (H2O).
Question 24:
When carboxylic acids and ammonia interact, what type of compound is formed?
Topic: Organic Chemistry - Reaction of Carboxylic Acids with Ammonia
Correct Answer: C) Ammonium salts
- Carboxylic acids and ammonia can combine in a chemical reaction to produce different compounds.
- Specifically, the interaction of ammonia (NH3) with a carboxylic acid, such as acetic acid (CH3COOH), leads to the formation of an ammonium salt, namely, ammonium acetate (CH3COONH4).
Question 25:
What is the result of the reaction between carboxylic acids and ammonia?
Topic: Organic Chemistry - Formation of Ammonium Salts
Correct Answer: C) Ammonium salts
- A reaction between a carboxylic acid and ammonia generally leads to the formation of a specific kind of compound.
- For instance, when acetic acid (CH3COOH) reacts with ammonia (NH3), ammonium acetate (CH3COONH4), an ammonium salt, is produced.
Question 26:
Which carboxylic acid is considered the most significant?
Topic: Organic Chemistry - Importance of Carboxylic Acids
Correct Answer: C) Acetic acid
- Carboxylic acids are a class of organic compounds containing a carboxyl functional group.
- Among them, acetic acid carries significant importance due to its wide use in industry and food, making it the most important carboxylic acid.
Question 27:
What is produced when carboxylic acids react with basic substances?
Topic: Organic Chemistry - Reaction of Carboxylic Acids with Bases
Correct Answer: D) Salts
- Reactions between acids and bases typically result in the formation of salts and water.
- In the case of carboxylic acids, a base such as sodium hydroxide (NaOH) reacts with acetic acid (CH3COOH) to yield a salt, sodium acetate (CH3COONa), and water (H2O).
Question 28:
In the reaction of carboxylic acids with nucleophiles, which group is typically replaced, leading to a derivative of the carboxylic acid?
Topic: Organic Chemistry - Nucleophilic Addition to Carboxylic Acids
Correct Answer: B) -OH group
- Nucleophilic addition is a fundamental type of reaction in organic chemistry, where a nucleophile forms a bond with an electrophile.
- In the case of carboxylic acids, the addition of a nucleophile is usually followed by the displacement of the -OH group, creating a derivative of the original carboxylic acid. For example, when acetic acid (CH3COOH) reacts with phosphorus pentachloride (PCl5), the -OH group is replaced by a -Cl group, forming acetyl chloride (CH3COCl), a derivative of acetic acid.
Question 29:
Which agent is typically utilized to reduce carboxylic acids?
Topic: Organic Chemistry - Reduction of Carboxylic Acids
Correct Answer: D) LiAlH4
- Reduction is a chemical reaction that primarily involves the gaining of electrons by a molecule, atom, or ion.
- Carboxylic acids can be reduced to alcohols using specific reducing agents.
- Among the choices, Lithium aluminum hydride (LiAlH4) is often employed as a powerful reducing agent that can convert carboxylic acids into alcohols.
Question 30:
What causes the relatively high boiling points of carboxylic acids?
Topic: Organic Chemistry - Physical Properties of Carboxylic Acids
Correct Answer: B) Hydrogen bonding
- The physical properties of organic compounds like carboxylic acids are heavily influenced by the types of intermolecular forces present.
- In the case of carboxylic acids, hydrogen bonding significantly contributes to their relatively high boiling points. This is because carboxylic acids can form two hydrogen bonds per molecule, leading to a comparatively stronger intermolecular attraction that requires more energy, and hence a higher temperature, to overcome.
Question 31:
What is the result of adding a nucleophile to carboxylic acids?
Topic: Organic Chemistry - Nucleophilic Addition to Carboxylic Acids
Correct Answer: B) -OH group
- Nucleophilic addition is a fundamental type of reaction in organic chemistry, where a nucleophile forms a bond with an electrophile.
- In the case of carboxylic acids, the addition of a nucleophile is usually followed by the displacement of the -OH group, creating a derivative of the original carboxylic acid.
- For example, when acetic acid (CH3COOH) reacts with phosphorus pentachloride (PCl5), the -OH group is replaced by a -Cl group, forming acetyl chloride (CH3COCl), a derivative of acetic acid.