(a)(i) What is the general formula for alkanoic acids?
(ii) State two chemical properties of ethanoic acid.
(b) Which of propene, butane and pentane
(i) will decolorize acidified KMnO(_4) solution?
(ii) can be easily polymerized?
(iii) is an isomer of methylpropane?
(iv) can be obtained from an alkanol by dehydration?
Explanation
(i) General formula for alkanoic acid is C(_n)H(_{2n + 1}) COOH. Two chemical properties of ethanoic acid
– Reacts with alkanols to form ethanoates or alkanoates or esters (esterification)
– Reacts with trioxocarbonate (IV) or hydrogen trioxocarbonate (IV) to produce carbon (IV) oxide
– Reacts with sodium hydroxide or potassium hydroxide to form sodium or potassium ethanoate.
(b)(i) Propene will decolorize acidified KMnO(_4) solution
(ii) Propene can easily be polymerised
(iii) Butane is an isomer of methylpropane
(iv) Propene can be obtained from alkanol by dehydration.