(a)(i) What is a functional group? (ii) State the functional group in each of the following compounds: I. CH\(_3\)CH\(_2\)CH(CH\(_3\))OH; II. CH\(_3\)CH\(_2...
Question 1 Report
(a)(i) What is a functional group?
(ii) State the functional group in each of the following compounds: I. CH\(_3\)CH\(_2\)CH(CH\(_3\))OH; II. CH\(_3\)CH\(_2\)CH\(_2\)COOH.
(b)(i) Complete the following equations:
(ii) Draw the structure(s) of the product(s) formed in (b)(i) above.
(c)(i).Write an equation for the prepzration of butan-2-ol from butene.
(d) (i) Give the reagents required for the following conversions to take place: I. CH\(_2\) = CH\(_2\) to CH\(_3\)CH\(_2\)OH; II. CH\(_3\)CH\(_2\)OH to CH\(_3\)COOH; Ill. CH\(_3\)COOH to CH\(_3\)COOCH\(_2\)CH\(_3\).
(e) Consider the following organic structure; CH\(_3\)OHCHCH = CHCOOH
(i) State what would be observed when the organic compound is treated with each of the following reagents: I. cold NaHCO\(_{3(aq)}\); II. hot solution of I\(_2\) in NaOH\(_{(aq)}\); Ill. bromine water.
Answer Details
(a)(i) A functional group is an atom or group of atoms in an organic compound that determines its characteristic chemical reactions.
(a)(ii)
- In CH3CH2CH(CH3)OH, the functional group is the hydroxyl group, OH.
- In CH3CH2CH2COOH, the functional group is the carboxyl group, COOH.
(b)(i) The completed equations are:
- \[\mathrm{CH_3COOCH_2CH_2CH_3 + H_2O \xrightarrow[\text{heat}]{H^+} CH_3COOH + CH_3CH_2CH_2OH}\]
- \[\mathrm{CH_3CH_2CH_2CH_2COOCH_3 + NaOH \xrightarrow{\text{heat}} CH_3CH_2CH_2CH_2COONa + CH_3OH}\]
(b)(ii) The displayed structures of the products are shown below.
(c)(i) Butan-2-ol is prepared from butene by acid-catalysed hydration:
\[\mathrm{CH_2{=}CHCH_2CH_3 + H_2O \xrightarrow{H^+\,/\,H_2SO_4} CH_3CH(OH)CH_2CH_3}\](d)(i)
- CH2=CH2 CH3CH2OH: steam and concentrated H2SO4 or H3PO4 catalyst.
- CH3CH2OH CH3COOH: acidified potassium dichromate(VI), K2Cr2O7/H2SO4, heat under reflux. Acidified KMnO4 is also suitable.
- CH3COOH CH3COOCH2CH3: ethanol and concentrated H2SO4, warmed.
(e)(i) For CH3CH(OH)CH=CHCOOH:
- With cold aqueous NaHCO3, brisk effervescence occurs as carbon dioxide is evolved.
\[\mathrm{RCOOH + NaHCO_3 \rightarrow RCOONa + H_2O + CO_2}\] - With hot iodine solution in aqueous sodium hydroxide, a yellow precipitate of iodoform, CHI3, is formed.
- Bromine water is decolourised, showing the presence of the carbon-carbon double bond.
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