Question 1

Which of the following best describes the principle behind solid-liquid extraction as performed in the lab?

Accepted Answer

It separates a desired compound from a mixture using its preferential solubility in a particular solvent.

Question 2

During an acid-base extraction, which of the following equations correctly represents the reaction of a carboxylic acid with aqueous sodium bicarbonate?

Accepted Answer

$$\mathrm{RCOOH + $$NaHCO_3$$ \rightarrow RCOONa + CO_2$ + H_2O}$$

Question 3

A student is performing a bromination reaction in the lab. Which safety precaution is most important due to the properties of bromine?

Accepted Answer

Working in a fume hood to avoid inhaling toxic vapors.

Question 4

In thin-layer chromatography (TLC), which factor most directly affects the $$R_f$$ value of a compound?

Accepted Answer

The polarity of the solvent used as the mobile phase.

Question 5

Which of the following best explains why a racemic mixture is optically inactive?

Accepted Answer

The optical activities of the two enantiomers cancel each other out.

Question 6

A student is asked to resolve a racemic amine using a chiral acid. Which of the following steps is essential in this process?

Accepted Answer

Formation of diastereomeric salts that can be separated by crystallization.

Question 7

Which of the following statements about the SN2 reaction mechanism is correct?

Accepted Answer

The reaction proceeds with inversion of configuration at the electrophilic carbon.

Question 8

In an IR spectrum, which functional group is indicated by a strong, broad absorption around $$3300\ \mathrm{cm}^{-1}$$?

Accepted Answer

Alcohol (O-H stretch)

Question 9

A student is synthesizing aspirin from salicylic acid and acetic anhydride. Which of the following best describes the role of acetic anhydride in this reaction?

Accepted Answer

It acetylates the phenolic hydroxyl group of salicylic acid.

Question 10

Which of the following is a correct statement about the resolution of racemic mixtures using chromatography?

Accepted Answer

Chiral stationary phases are required to separate enantiomers by chromatography.

Question 11

During the synthesis of banana oil (isoamyl acetate), which type of reaction is primarily involved?

Accepted Answer

Esterification

Question 12

A student is analyzing a mixture using column chromatography. Which of the following will elute first from a silica gel column when using a non-polar solvent?

Accepted Answer

The least polar compound

Question 13

Which of the following best explains why SN2 reactions are faster in polar aprotic solvents?

Accepted Answer

Polar aprotic solvents do not solvate anions well, increasing nucleophilicity.

Question 14

A student observes two spots on a TLC plate after developing a sample. What is the most likely explanation?

Accepted Answer

The sample contains at least two different compounds.

Question 15

Which of the following is the correct balanced equation for the synthesis of aspirin from salicylic acid and acetic anhydride?

Accepted Answer

$$\mathrm{C_7H_6O_3 + (CH_3CO)_2O \rightarrow C_9H_8O_4 + CH_3COOH}$$

Question 16

In the context of IR spectroscopy, which of the following functional groups would show a sharp absorption near $$1700\ \mathrm{cm}^{-1}$$?

Accepted Answer

Ketone

Question 17

A student is tasked with separating a mixture of benzoic acid and benzil using acid-base extraction. Which solvent system should be used to extract benzoic acid into the aqueous layer?

Accepted Answer

Aqueous sodium hydroxide

Question 18

Which of the following statements about the use of ChemDraw in organic chemistry labs is correct?

Accepted Answer

ChemDraw is used to draw and visualize chemical structures and reaction mechanisms.

Question 19

A student is performing the synthesis of aspirin and observes a low yield. Which of the following is the most likely cause?

Accepted Answer

Incomplete reaction due to insufficient acetic anhydride.

Question 20

Which of the following best describes the purpose of a lab coat and goggles in the organic chemistry laboratory?

Accepted Answer

To protect against chemical spills and splashes.

Organic Chemistry Laboratory Course Schedule and Key Experiments

Guida di studio - Domande di pratica

Study guide - Flashcard