$$CH_3C \\equiv CH \u003e CH_2$=CH_2$ \u003e CH_3CH_3$$

$$CH_3CH_2C \\equiv CH$$ and $$CH_3CH=CH_2$

Question 1

Which of the following best describes the geometry around each carbon atom in acetylene ($$C_2H_2$$)?

Accepted Answer

Linear

Question 2

What is the IUPAC name for the compound with the structure $$CH_3C \equiv CCH_2CH_3$$?

Accepted Answer

2-pentyne

Question 3

Which of the following statements about alkynes is CORRECT?

Accepted Answer

Alkynes have higher boiling points than alkanes of similar molecular weight due to increased polarity.

Question 4

Which of the following is a correct product of the reaction of 1-butyne with excess $$Br_2 in$$ $$CCl_4$$?

Accepted Answer

1,1,2,2-tetrabromobutane

Question 5

Which of the following is the correct order of acidity (most acidic to least acidic)?

Accepted Answer

$$CH_3C \equiv CH \u003e CH_2$=CH_2$ \u003e CH_3CH_3$$

Question 6

Which of the following reagents can be used to distinguish between an alkyne and an alkene?

Accepted Answer

Ammoniacal silver nitrate ($$Ag(NH_3$)_2^+)$$

Question 7

What is the product when 2-butyne is treated with excess $$H_2 in $$the presence of Lindlar's catalyst?

Accepted Answer

cis-2-butene

Question 8

Which of the following best describes the Markovnikov addition of $$HBr to 1-$$pentyne?

Accepted Answer

The bromine atom adds to the more substituted carbon of the triple bond.

Question 9

Which of the following is a correct statement about the preparation of alkynes?

Accepted Answer

Alkynes can be prepared by the dehydrohalogenation of vicinal dihalides.

Question 10

Which of the following is the correct IUPAC name for the compound $$CH_3CH_2C \equiv $$CCH_3$$?

Accepted Answer

3-pentyne

Question 11

Which of the following reactions will produce a terminal alkyne?

Accepted Answer

Dehydrohalogenation of 1,2-dibromopropane

Question 12

Which of the following is a product of the hydroboration-oxidation of 1-hexyne?

Accepted Answer

Hexanal

Question 13

Which of the following best explains why alkynes are more acidic than alkenes and alkanes?

Accepted Answer

The sp-hybridized carbon in alkynes holds electrons closer to the nucleus, stabilizing the conjugate base.

Question 14

Which of the following is the correct product when 1-hexyne reacts with $$HgSO_4$$ and $$H_2SO_4$$?

Accepted Answer

2-hexanone

Question 15

Which of the following is a correct statement about the addition of $$Br_2 to an $$alkyne?

Accepted Answer

The reaction proceeds via a cyclic bromonium ion intermediate.

Question 16

Which of the following is a correct example of functional isomerism in alkynes?

Accepted Answer

$$CH_3CH_2C \equiv CH$$ and $$CH_3CH=CH_2$

Question 17

Which of the following best describes the product of the oxidative cleavage of an internal alkyne with $$KMnO_4$$?

Accepted Answer

Two carboxylic acids

Question 18

Which of the following is the correct product when 1-butyne reacts with $$NaNH_2$$ followed by $$CH_3Br$$?

Accepted Answer

2-pentyne

Question 19

Which of the following is a correct statement about the reduction of alkynes with sodium in liquid ammonia?

Accepted Answer

It produces trans-alkenes.

Unsaturated Hydrocarbons – Alkynes: Structure, Nomenclature, Properties, Preparations, Reactions & Organic Synthesis

Study Guide - Practice Questions