Question 1

Which of the following correctly describes the IUPAC naming rule for alkynes?

Accepted Answer

The longest chain must contain the triple bond, and numbering starts from the end closest to the triple bond.

Question 2

What is the correct IUPAC name for the following compound: $$CH_3C\equiv CCH_2CH_3$$?

Accepted Answer

2-pentyne

Question 3

Which of the following statements about terminal and internal alkynes is correct?

Accepted Answer

Terminal alkynes have the triple bond at the end of the carbon chain, while internal alkynes have it between two carbons.

Question 4

When 1-butyne reacts with $$HBr$$, which product is formed according to Markovnikov's rule?

Accepted Answer

$$CH_3CH_2CHBrCH_2Br$$

Question 5

Which reagent is used for the anti-Markovnikov hydration of a terminal alkyne to produce an aldehyde?

Accepted Answer

$$BH_3$$, $$H_2O_2$$, $$NaOH$$

Question 6

What is the major product when 2-butyne is treated with excess $$Br_2 in$$ $$CCl_4$$?

Accepted Answer

$$CH_3CBr_2CBr_2CH_3$$

Question 7

Which of the following best describes the product of complete hydrogenation of an alkyne?

Accepted Answer

An alkane

Question 8

What is the product when a terminal alkyne undergoes hydration with $$HgSO_4$$ and $$H_2SO_4$$?

Accepted Answer

A methyl ketone

Question 9

Which catalyst is used to selectively hydrogenate an alkyne to a cis-alkene?

Accepted Answer

Lindlar catalyst

Question 10

What is the product of oxidative cleavage of an internal alkyne using $$KMnO_4$$?

Accepted Answer

Two carboxylic acids

Question 11

Which of the following is true about enol-keto tautomerization after hydration of alkynes?

Accepted Answer

The enol form is unstable and rapidly converts to the keto form.

Question 12

Which of the following reagents will convert a terminal alkyne to a trans-alkene?

Accepted Answer

$$Na/NH_3$

Question 13

What is the product when acetylene ($$HC\equiv CH) is $$treated with excess $$Br_2$$?

Accepted Answer

$$CHBr_2CHBr_2$$

Question 14

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, stabilizing the negative charge on the conjugate base.

Question 15

Which of the following is a correct product of ozonolysis of an internal alkyne?

Accepted Answer

Two carboxylic acids

Question 16

What is the major product when 1-hexyne is treated with $$BH_3$$, $$H_2O_2$$, and $$NaOH$$?

Accepted Answer

Hexanal

Question 17

Which of the following reactions will produce a cis-alkene from an alkyne?

Accepted Answer

Hydrogenation with Lindlar catalyst

Question 18

Which of the following is a common misconception about the addition of $$HX to $$alkynes?

Accepted Answer

Both additions are Markovnikov, leading to geminal dihalide formation.

Question 19

Which of the following best describes the product of hydroboration-oxidation of a terminal alkyne?

Accepted Answer

An aldehyde

Alkynes: Naming, Properties, and Reactions – Comprehensive Study Notes

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