Unsaturated hydrocarbons

2 marks · Hard

State the name and draw the displayed formula of the alkene that has four carbon atoms in a continuous chain with the double bond between the second and third carbon atoms.

Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.

Show answer

Name: but-2-ene; Displayed formula: CH3–CH=CH–CH3 (all bonds shown)

Must show: All C and H atoms shown, Double bond between second and third carbon atom

Also accept: Structural formula accepted if clear and labels are present

Common mistakes: Incorrect position of double bond; Writing 'but-1-ene' or drawing double bond at the end

Show mark scheme and worked solution

Marking points

N1 · 1 mark · Correctly states the name 'but-2-ene'.

D1 · 1 mark · Correctly draws the displayed formula with four carbons in a chain, double bond between C2 and C3 (CH3–CH=CH–CH3), showing all bonds.

Worked solution

Name: but-2-ene