intro
MCQs 1:
Which form(s) can carboxylic acid take?
Topic: Types of Carboxylic Acids
Correct Answer: C) Both A and B
- Carboxylic acids can occur in various forms, and both aliphatic and aromatic structures are possible.
- In an aliphatic carboxylic acid, the functional group COOH is attached to a straight or branched chain of carbon atoms (R-COOH).
- In the case of aromatic carboxylic acids, the COOH is attached to an aromatic (Ar) group, typically a phenyl group (Ar-COOH).
MCQs 2:
What can carboxylic acids be reduced to when reacted with LiAlH4?
Topic: Reactions of Carboxylic Acids
Correct Answer: B) Alcohols
- The reduction reaction of carboxylic acids is not as straightforward as with aldehydes, ketones, or esters.
- Carboxylic acids can be reduced to primary alcohols specifically when using Lithium aluminium hydride (LiAlH4), a strong reducing agent.
MCQs 3:
What is the product formed when acetic acid reacts with PCl5?
Topic: Reactions of Acetic Acid
Correct Answer: B) CH3COCl
- The reaction of acetic acid with phosphorus pentachloride (PCl5) results in the formation of acetyl chloride (CH3COCl).
- Side products of this reaction include phosphorus oxychloride (POCl3) and hydrochloric acid (HCl).
MCQs 4:
Which of the following substances will yield acetic acid upon oxidation?
Topic: Oxidation Reactions to form Acetic Acid
Correct Answer: A) Ethanol
- The oxidation of alcohols can produce a variety of products.
- In the case of ethanol, its oxidation leads to the formation of acetic acid.
MCQs 5:
Which of the following organic acids lacks a carboxyl group?
Topic: Organic Acid Structures
Correct Answer: B) Picric acid
- Organic acids typically contain a carboxyl group as a fundamental feature of their structure.
- Picric acid, also known as Trinitrophenol, is an exception to this rule as it does not contain a carboxyl group.
MCQs 6:
What class of compounds is produced when carboxylic acids react with alcohols?
Topic: Reactions of Carboxylic Acids
Correct Answer: B) Esters
- Carboxylic acids react with alcohols in a process known as esterification.
- The outcome of this reaction is the formation of esters.
MCQs 7:
What is the IUPAC name for caproic acid?
Topic: Nomenclature of Carboxylic Acids
Correct Answer: B) Hexanoic acid
- IUPAC nomenclature is a systematic method of naming chemical compounds as recommended by the International Union of Pure and Applied Chemistry (IUPAC).
- Caproic acid, derived from hexane, is officially named Hexanoic acid with the chemical formula CH3(CH2)4COOH.
Question 8:
What is the name of the reaction that occurs when alcohol reacts with acetic acid?
Topic: Esterification
Correct Answer: B) Esterification
- The combination of an alcohol and acetic acid results in a particular type of chemical reaction.
- This reaction results in the formation of an ester and is therefore termed as esterification.
Question 9:
What physical state are the first three aliphatic acids typically in?
Topic: Properties of Aliphatic Acids
Correct Answer: A) Liquids
- Aliphatic acids, such as formic acid, acetic acid, and propionic acid, have unique physical properties.
- Notably, these first three aliphatic acids are colorless and exist in a liquid state.
Question 10:
Which of the following is identified as a strong reducing agent?
Topic: Reducing Agents
Correct Answer: D) Chloroacetic acid
- Reducing agents are substances that lose or "donate" electrons in a chemical reaction.
- Chloroacetic acid is recognized as a strong reducing agent owing to its high acidic strength.
Question 11:
What substance is found in the stings of bees and wasps?
Topic: Composition of Animal Stings
Correct Answer: B) Formic acid
- Animal stings, particularly those of bees and wasps, contain specific substances that cause irritation.
- Formic acid, represented by the chemical formula HCOOH, is the primary substance present in these stings. The discomfort caused by stings is largely due to this acid.
Question 12:
What is used as a coagulant for latex in the rubber industry?
Topic: Industrial Use of Acids
Correct Answer: A) Acetic acid
- Certain acids are used in industry for specific purposes.
- In the rubber industry, acetic acid, CH₃COOH, is commonly employed as a coagulant for latex.
Question 13:
What is the correct order of ease of esterification of the following acids with CH3OH?
I. HCOOH
II. CH3COOH
III. CH3CH2COOH
Topic: Esterification of Acids
Correct Answer: D) III < II < I
- The process of esterification varies depending on the size and structure of the alkyl group in the carboxylic acid (R–COOH).
- The ease of esterification tends to be greater with smaller alkyl groups.
Question 14:
What is the characteristic that gives the name 'glacial' to pure acetic acid?
Topic: Physical Properties of Acetic Acid
Correct Answer: B) It forms an ice-like solid below 17˚C
- The term 'glacial' is used to describe certain physical properties of acetic acid.
- Notably, pure acetic acid takes on an ice-like solid form when cooled below 17˚C, hence the name 'glacial acetic acid'.
Question 15:
Which of the following agents can directly reduce carboxylic acid to primary alcohols?
Topic: Reduction of Carboxylic Acid
Correct Answer: A) LiAlH4
- Carboxylic acids can be reduced to primary alcohols using certain agents.
- Among the options listed, LiAlH4 (lithium aluminium hydride) is recognized as a strong reducing agent capable of directly converting carboxylic acids into primary alcohols.
Question 17:
Which substance among the following has both hydroxyl and carboxylic acid groups?
Topic: Identification of Functional Groups
Correct Answer: D) Salicylic acid
- Functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules.
- Among the given options, salicylic acid is unique because it contains both a hydroxyl group (-OH) and a carboxylic acid group (-COOH).
Question 18:
What is the general formula for aliphatic carboxylic acid?
Topic: Formulas of Organic Compounds
Correct Answer: C) CnH2nO2
- Organic compounds are a broad class of substances characterized by carbon-based molecules. They have specific general formulas that provide a simplified representation of their chemical structure.
- The general formula for aliphatic carboxylic acids is CnH2nO2, which indicates the presence of a carboxyl functional group (-COOH) in these compounds.
Question 19:
Which among the following substances is associated with an orange flavor?
Topic: Flavor Profiles of Chemical Compounds
Correct Answer: B) Octyl Acetate
- Certain chemicals are known to contribute specific flavors or aromas to foods and other substances.
- Octyl acetate, for instance, is associated with an orange flavor. This ester is often used in the production of artificial flavors due to its distinctive citrus aroma.
Question 20:
What is the boiling point of formic acid?
Topic: Physical Properties of Acids
Correct Answer: A) 100°C
- The boiling point of an acid is the temperature at which it transitions from a liquid to a gas.
- Formic acid, also known as methanoic acid, has a boiling point of 100°C, which is a fundamental aspect of its physical properties.
Question 21:
What is the IUPAC name for a carboxylic acid that contains three carbon atoms?
Topic: Nomenclature of Organic Compounds
Correct Answer: C) Propanoic acid
- The International Union of Pure and Applied Chemistry (IUPAC) provides the universally accepted naming system for organic compounds.
- In this system, a carboxylic acid with three carbon atoms is named propanoic acid, following the rule that the prefix 'prop-' indicates the presence of three carbon atoms.
Question 22:
Which test is commonly used for the identification of amino acids?
Topic: Biochemical Test for Amino Acids
Correct Answer: A) Ninhydrin test
- Different tests are used in biochemistry to detect and identify amino acids.
- The Ninhydrin test is particularly recognized for its effectiveness in identifying amino acids, as it reacts with these molecules to form a characteristic bluish-violet product, making it an essential tool in biochemical analysis.
Question 23:
What is another name for 2-Hydroxy propionic acid?
Topic: Nomenclature of Organic Acids
Correct Answer: B) Lactic acid
- Organic acids can have both a scientific name and a common name, which are often used interchangeably.
- 2-Hydroxy propionic acid is commonly known as lactic acid.
Question 24:
What is the description of Glacial acetic acid?
Topic: Characteristics of Organic Acids
Correct Answer: D) Pure acetic acid at 17°C
- The term "glacial" is used to describe the physical state of acetic acid when it freezes, which occurs at 17°C.
- Therefore, glacial acetic acid refers to the pure, undiluted substance at 17°C.
Question 25:
In what kind of solution does carboxylic acid exist as a cyclic dimer?
Topic: Physical Behavior of Carboxylic Acids
Correct Answer: C) Benzene
- Carboxylic acids can form a cyclic dimer structure due to hydrogen bonding when in a specific type of solution.
- In the case of benzene, which is non-polar, carboxylic acid will exist as a cyclic dimer.
Question 26:
How many essential amino acids are there?
Topic: Classification of Amino Acids
Correct Answer: B) 10
- Amino acids are categorized into two groups: essential and non-essential.
- Essential amino acids are those that the human body cannot produce on its own and must obtain through diet. There are 10 such essential amino acids.
Question 27:
What is the term for the reaction between a fat and caustic soda?
Topic: Chemical Reactions of Fats
Correct Answer: D) Saponification
- Different reactions can occur between fats and other substances.
- The reaction between a fat and caustic soda specifically results in the production of soap and is known as saponification.
Question 28:
Which acid's solution is typically used for seasoning food?
Topic: Usage of Acids in Culinary
Correct Answer: B) Acetic acid
- Acids have various uses, including in the culinary world.
- Acetic acid, in particular, is used as a souring agent in foods like vinegar and pickled vegetables, contributing to their unique flavors.
Question 29:
Why does acetic acid exhibit a molecular mass of 120 when dissolved in benzene?
Topic: Behavior of Acetic Acid in Different Solvents
Correct Answer: D) As a result of dimerization
- The observed molecular mass of a substance can be influenced by its behavior in different solvents.
- When acetic acid is dissolved in benzene, it forms a dimer structure, which effectively doubles its molecular mass. Hence, the observed molecular mass is 120.
Question 30:
Which acid is used in the production of synthetic rubber?
Topic: Industrial Applications of Acids
Correct Answer: A) Acetic acid
- Various acids have diverse applications in the industrial sector.
- Acetic acid is specifically used as a coagulant in the rubber industry during the manufacture of synthetic rubber.
Question 31:
What is the role of acetic acid in the laboratory?
Topic: Laboratory Applications of Acids
Correct Answer: D) As a solvent for carrying out reactions
- Acids are not only used in industries but also have significant roles in scientific laboratories.
- Particularly, acetic acid is used as a solvent in laboratories for carrying out various reactions.