Quiz

QUIZ

1. An amine called dimethyl ethylamine is what type of amine compound?

a. Primary amine b. Secondary amine c. Tertiary amine d. Quaternary amine

Answer: c. This amine clearly has three alkyl groups associated with it, making it a tertiary amine. A primary amine has one alkyl or aryl group, while a secondary amine has two alkyl or aryl groups attached to it.

2. What would the charge be on tetramethylammonium, which has four alkyl groups attached?

a. +1 b. +2

c. +3 d. 0

Answer: a. This would be an ammonium ion that would have a single positive charge associated with it, which would essentially be no different from a regular NH4+ ammonium cation.

3. Which amine compound is charged?

a. Primary amine b. Secondary amine c. Tertiary amine d. Quaternary amine

Answer: d. A quaternary amine has four alkyl groups around a nitrogen compound. Because neutral nitrogen compounds have three hydrogen atoms or up to three alkyl groups, having a fourth would mean there is a positive charge on the compound.

4. What is something that will not happen to a compound by virtue of having an

N-H bond versus an alkane of the same size?

a. Decreased water solubility b. Increased melting point c. Increased boiling point d. Increased hydrogen bonding

Answer: a. This NH bond will be polar, leading to increased hydrogen bonding, increased melting point, increased boiling point and increased water solubility.

5. In the nucleophilic substitution reaction that makes up an alkyl amine, what is the reactant besides ammonia?

a. Alkane b. Alcohol c. Carboxylate d. Alkyl halide

Answer: d. The alkyl halide group is the easiest to substitute with the amine group, with the nitrogen being the nucleophile and the alkyl carbon being the electrophile.

6. How can the reaction of an alkyl halide and ammonia yield mostly a primary amine versus a mixture of amines?

a. Limit the ammonia b. Have a large excess of ammonia c. Make the reaction in basic circumstances d. Make the reaction in acidic circumstances

Answer: b. The reaction will yield a majority of a primary amine if the reaction is done with a large excess of ammonia in the reaction.

7. What is the oxidation state of the carbon atom in the RCH2NH2 molecule?

a. +3 b. 0

c. -1 d. b. -3

Answer: c. The hydrogen atoms are positive, leading to a -2-oxidation state. This is added to the +1 for the nitrogen-carbon bond, leading to a total of -1 oxidation state for the carbon molecule.

8. What is a good reducing agent for the reduction of azides and nitriles?

a. H2SO4 b. H2 gas c. HCl d. LiAlH4

Answer: d. The best reducing agent for these types of reactions is LiAlH4, which provides a great number of hydrogen ions. H2 gas can do this but it requires a palladium catalyst.

9. What can be added to an amine molecule to make an amide molecule?

a. Ketone b. Acid chloride (acyl chloride) c. Aldehyde d. Imine

Answer: b. This takes an acid chloride (acyl chloride) or alternatively an acid anhydride. These will be able to be separated in an acyl nucleophilic substitution reaction to make an amide molecule. These reactions are possible because of the nucleophilicity of the nitrogen molecule when compared to that of the oxygen and chloride molecule in acid chlorides and acid anhydrides.

10. The nitrosation of aryl compounds will lead to aryl diazonium cations, which are unstable and lead to an aryl group that can be substituted with a variety of compounds. What is the reactant in the nitrosation reaction of primary amines besides the amines?

a. NH4+Cl b. HNO3 c. HNO2 d. Alkyl nitrate

Answer: c. The reactant is an aryl amine plus the HNO2 molecule or “nitrous acid”. This gives rise to the diazonium cation, an unstable molecule that forms a carbo-cation (a positively-charged carbon atom), also an unstable molecule that can be substituted.