AS Level CIE Intro to Organic

Pentanol, C₅H₁₁OH, has four structural isomers that are primary alcohols. How many of these primary alcohols contain a chiral carbon atom?

• 0

• 1

• 2

• 3

The diagram shows the structure of the naturally-occurring molecule cholesterol. Student X claimed that the seventeen carbon atoms in the four rings all lie in the same plane. Student Y claimed that this molecule displays cis-trans isomerism at the C=C double bond. Which of the students are correct?

• both X and Y

• neither X nor Y

• X only

• Y only

Which compound does not show cis-trans isomerism?

• 2-methylpent-2-ene

• 3-methylpent-2-ene

• 3,4-dimethylhex-3-ene

• pent-2-ene

Which formulae show propanone and propanal as different compounds?

• empirical, molecular, structural and displayed formulae

• molecular, structural and displayed formulae only

• structural and displayed formulae only

• displayed formulae only

How many isomers with the formula C₅H₁₀ have structures that involve π bonding?

• 3

• 4

• 5

• 6

How many isomeric esters have the molecular formula C₄H₈O₂?

• 2

• 3

• 4

• 5

Which diagram gives the skeletal formula of 2-chloropentan-3-ol?

• Diagram A

• Diagram B

• Diagram C

• Diagram D

Isomers X and Y both react with HBr. A mixture of X and Y is reacted with HBr. Which three structures represent three different possible products of this reaction?

• (CH₃)₂CHCBr₃

• CH₃CBr₂CHBrCH₃

• CHBr₂CBr(CH₃)CH₃

• CH₃CHBrCBr₂CH₃

• (CH₃)₂CBrCHBr₂

The following compounds are found in the seaweed Asparagopsis taxiformis. Which compound could show both cis-trans isomerism and optical isomerism?

• Compound A

• Compound B

• Compound C

• Compound D

Pentane, C₅H₁₂, is reacted with chlorine in the presence of ultraviolet light. A compound R is found in the products. R has molecular formula C₅H₁₀Cl₂. Each molecule of R contains one chiral carbon atom. Which two atoms of the pentane chain could be bonded to chlorine atoms in this isomer?

• 1 and 3

• 1 and 5

• 2 and 3

• 2 and 4