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CAIE A-Level Chemistry 14.2.2 Reactions of Alkenes

Practise alkene addition, oxidation and polymerisation reactions and deducing C=C positions from cleavage products.

Syllabus
2028–2030
Course
Chemistry 9701
Level
AS

Exam points

  • select H2/Ni, steam/H3PO4, HX or X2 for addition across C=C and draw the product
  • use cold dilute acidified KMnO4 for a diol and hot concentrated reagent for oxidative cleavage
  • reconstruct the original alkene from ketone, acid, CO2 or water cleavage products and stoichiometry

14.2.2—Reactions of alkenes question 1

[Maximum number: 1]

Organic compounds can be distinguished using chemical tests and analytical techniques.

Organic compound E contains three carbon atoms. E reacts with cold dilute acidified KMnO4(aq)\mathrm{KMnO}_{4}(\mathrm{aq}) to form a single compound F with Mr=154.9M_{\mathrm{r}}=154.9.
Fig. 3.1 shows the infrared spectrum of E.
Fig. 3.2 shows the infrared spectrum of F.

Fig. 3.1

Fig. 3.1

Fig. 3.2

Fig. 3.2

Table 3.2

Table 3.2

Both spectra show absorptions between 2850 and 2950 cm−12950 \mathrm{~cm}^{-1} owing to C-H bonds in each molecule.

Complete the equation for the reaction of E with cold dilute acidified KMnO4(aq)\mathrm{KMnO}_{4}(\mathrm{aq}) to form F. In the equation, [O][\mathrm{O}] represents cold dilute acidified KMnO4(aq)\mathrm{KMnO}_{4}(\mathrm{aq}).

H2O+[O]+\mathrm{H}_{2} \mathrm{O}+[\mathrm{O}]+

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