PMOD (2017)

Question 1

What is the difference between structural and geometric isomers? (2)

Answer 1

• Structural isomers have the same molecular formula, but atoms are bounded in a different order.
• Geometrical isomers have the same molecular formula and atoms bound in the same order, but different arrangement around the C-C double bond

Question 2

Explain the difference between a saturated and an unsaturated hydrocarbon, and what test can be used to differentiate them. Give expected observations that would confirm saturation and
unsaturation. (5)

Answer 2

• Saturated hydrocarbons only contain single bonds between carbons.
• Unsaturated hydrocarbons contain at least one double or triple bond between carbons
• Test by shaking with some bromine water
• Saturated mixture remains orange
• Unsaturated mixture fades/turns colourless