Page 158 - Jurnal Pendidikan Tingkatan Enam 2019 - Jilid 3

Perubahan Paradigma Pemikiran Ke Arah Pendidikan Berkualiti

LAMPIRAN 3
LAMPIRAN 3

CONTOH SOALAN ESEI PENGENALPASTIAN FORMULA STRUKTUR
SEBATIAN-SEBATIAN ORGANIK DENGAN MENGGUNAKAN TEKNIK TODA

Group 1:

Compound R and S are two isomers with molecular formula C8H10O. R gives off white
fumes with thionyl chloride and forms a yellow precipitate with alkaline aqueous iodine
but S does not. S dissolves in aqueous potassium hydroxide but R does not. R is
synthesised starting from bromobenzene whereas S from 4-ethylaniline.
Explain the above observations and write the structural formulae of R and S.[5 m]

Write the equations where appropriate. [4 m]

Group 2:

Compound A, with the molecular formula C5H12O, which has a straight chain structure
is an optically active alcohol. When A is heated with alumina, compounds B and C are
formed. B shows geometrical isomerism but C does not. When C is heated with an
acidified potassium manganate (VII) solution, compound D is formed and a gas which
turns lime water chalky is evolved. When D is heated with an aqueous solution of
ammonia, compound E is formed which reacts with liyhium tetrahydridoaluminate(III)
to form compound F.
Write the structural formulae of compounds A, B, C, D, E and F. [10 m]

Group 3:
A type of solvent used in the paint industry contains the organic compound D. When
substance D reacts with 2,4-dinitrophenylhydrazine, an orange precipitate is obtained.
With an alkaline iodine solution, D forms a yellow precipitate. But D does not react with
hot acidified potassium dichromate(VI) solution. D also does not react with bromine
water. The catalytic reduction of compound D with hydrogen produces two isomers, E
and F with the molecular formula C4H10O.
(a) Identify D, E and F. Explain your answer. [9 m]
(b) Write a balanced equation for the reaction of compound D with alkaline iodine
solution. [1 m]

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