Reactions of Some Aliphatic Compounds with Oxygen-Containing Functional Groups Present - Practical 4

Instructions: Please watch the Practical 4 video recording and make note of all amounts and structures of starting materials and products that were used in this practical. Then answer the quiz questions.

Experiment 4: Reactions of Some Aliphatic Compounds with Oxygen-Containing Functional Groups Present.

Q1: Structures of which three unknown compounds were established in the course of the practical?

• Amide, carboxylic acid and ketone
• Alcohol, carboxylic acid and a ketone
• Acid anhydride, alcohol and ketone
• Alcohol, aldehyde and ester

Q2: Which unknown compound solution gave red colour on test with pH paper?

• Alcohol
• Carboxylic acid
• Ketone
• None of the three unknowns

Q3: Which test confirmed the nature of the unknown compound as carboxylic acid?

• Preparation of semicarbazone
• Fehling's test
• Brady's test
• Reaction with sodium carbonate

Q4: Brady's test resulted in formation of which compound?

• Salt (carboxylic acid and amine)
• Hydrazone
• Ester
• Semicarbazone

Q5: What indicates a positive Fehling's test?

• Formation of white solid precipitate
• Formation of Cu(I) precipitate
• Evolution of carbon dioxide bubbles

Q6: What was the role of sodium acetate in the formation of semicarbazone?

• Sodium acetate had no role in this experiment
• Sodium acetate removed hydrochloric acid from commercial semicarbazide htdrochloride
• Sodium acetate worked as a dehydrating agent
• Sodium acetate reacted with the ketone

Q7: Which reagent was the limiting reagent in the reaction of the ketone with semicarbazide hydrochloride (remember to include HCl in your calculation)?

• emicarbazide hydrochloride
• No answer text provided.
• Sodium acetate
• Ketone

Q8: What was the structure of the product of the reaction of ketone with semicarbazide?

• Compound D
• Compound B
• Compound C
• Compound A

Q9: What was the role of sulfuric acid in the ester formation?

• Activation of the carboxylc acid towards reaction with the alcohol
• It was the solvent
• It had no role in the reaction
• It activated the OH of the alcohol to become a better leaving group

Q10: Why was the esterification performed?

• To dorm the salt of the carboxylic acid
• To establish the structures of unknown acid and alcohol
• To establish the melting point of the ester.
• To find out which compound was used in access

Q11: Please calculate the chemical yield (%) of the esterification reaction