Q. In a reaction mechanism, what is the term for a species that is formed in one step and consumed in a subsequent step?
A.Intermediate
B.Catalyst
C.Transition state
D.Reactant
Solution
An intermediate is a species that is produced in one step of a reaction mechanism and consumed in a later step.
Correct Answer: A — Intermediate
Q. What is the IUPAC name for the compound with the formula CH3-CH(CH3)-CH2-CH3?
A.2-Methylbutane
B.3-Methylbutane
C.Butane
D.Pentane
Solution
The longest carbon chain has four carbons (butane), and there is a methyl group on the second carbon, making it 2-Methylbutane.
Correct Answer: A — 2-Methylbutane
Q. What is the product of the reaction between an alcohol and a carboxylic acid in the presence of an acid catalyst?
A.Ester
B.Ether
C.Aldehyde
D.Ketone
Solution
The reaction between an alcohol and a carboxylic acid in the presence of an acid catalyst produces an ester through a process called esterification.
Correct Answer: A — Ester
Q. What is the rate law for the reaction A + B → C if the rate is found to be first order in A and second order in B?
A.Rate = k[A][B]
B.Rate = k[A]^2[B]
C.Rate = k[A][B]^2
D.Rate = k[A]^2[B]^2
Solution
The rate law is determined by the orders of the reactants. Since the reaction is first order in A and second order in B, the rate law is Rate = k[A][B]^2.
Correct Answer: C — Rate = k[A][B]^2
Q. What type of isomerism is exhibited by 2-butene?
A.Structural isomerism
B.Geometric isomerism
C.Optical isomerism
D.Conformational isomerism
Solution
2-butene exhibits geometric isomerism (cis/trans) due to the restricted rotation around the double bond.
Correct Answer: B — Geometric isomerism
Q. Which of the following compounds is a primary alcohol?
A.CH3CH2OH
B.CH3CHO
C.CH3CH2CH2OH
D.C6H5CH2OH
Solution
A primary alcohol is one where the hydroxyl group (-OH) is attached to a carbon that is only connected to one other carbon. CH3CH2OH (ethanol) is a primary alcohol.
Correct Answer: A — CH3CH2OH
Q. Which of the following functional groups is present in amino acids?
A.Carboxyl group
B.Hydroxyl group
C.Carbonyl group
D.Aldehyde group
Solution
Amino acids contain both an amino group (-NH2) and a carboxyl group (-COOH), making the carboxyl group a key functional group.
Correct Answer: A — Carboxyl group
Q. Which of the following is a characteristic of a zero-order reaction?
A.Rate depends on the concentration of reactants.
B.Rate is constant and independent of reactant concentration.
C.Rate increases with temperature.
D.Rate decreases as the reaction proceeds.
Solution
In a zero-order reaction, the rate is constant and does not depend on the concentration of the reactants.
Correct Answer: B — Rate is constant and independent of reactant concentration.
Q. Which of the following statements about reaction mechanisms is true?
A.All reactions proceed through a single elementary step.
B.Catalysts are consumed in the reaction.
C.The rate-determining step is the slowest step in a mechanism.
D.Intermediates are always stable.
Solution
The rate-determining step is indeed the slowest step in a reaction mechanism, which controls the overall rate of the reaction.
Correct Answer: C — The rate-determining step is the slowest step in a mechanism.
