Half-fill the $$\(250 \mathrm{~cm}^{3}\)$$ beaker with water and place it on a tripod and gauze. Heat the water until boiling then switch off your Bunsen burner. This is your hot water bath for use in (b). FA 8 is an organic liquid containing one functional group and only the elements $$\(\mathrm{C}, \mathrm{H}\)$$ and O . You will carry out two tests to investigate FA 8. For each test you will record your observations and then conclude one of the following: - at least two types of compound that FA 8 could be or - one type of compound that FA 8 cannot be. (i) To a 1 cm depth of FA 8 in a test-tube, add a few drops of acidified aqueous potassium manganate(VII), then place the test-tube in the hot water bath. observation . conclusion (ii) To a 1 cm depth of FA 8 in a test-tube, add a small spatula measure of sodium carbonate. observation . conclusion (iii) Suggest a further test you could carry out to identify one of the types of compound that you have concluded could be FA 8. State the reagent you would use. State what a positive result would indicate about the identity of FA 8. Do not carry out your test. reagent conclusion from a positive result .
Exam No：9701_s25_qp_35 Year：2025 Question No：3(b)
Answer:
Knowledge points:
14.2.1.1 elimination of HX from a halogenoalkane by ethanolic NaOH and heat
14.2.1.2 dehydration of an alcohol, by using a heated catalyst
14.2.1.3 cracking of a longer chain alkane
14.2.2.1.1 hydrogen in a hydrogenation reaction, and Pt/Ni catalyst and heat
14.2.2.1.2 steam, catalyst
14.2.2.1.3 a hydrogen halide, HX(g) at room temperature
14.2.2.1.4 a halogen,
14.2.2.2 the oxidation by cold dilute acidified to form the diol
14.2.2.3 the oxidation by hot concentrated acidified leading to the rupture of the carbon–carbon double bond and the identities of the subsequent products to determine the position of alkene linkages in larger molecules
14.2.2.4 addition polymerisation exemplified by the reactions of ethene and propene
14.2.3 describe the use of aqueous bromine to show the presence of a C=C bond
14.2.4 describe the mechanism of electrophilic addition in alkenes, using bromine / ethene and hydrogen bromide / propene as examples
14.2.5 describe and explain the inductive effects of alkyl groups on the stability of primary, secondary and tertiary cations formed during electrophilic addition (this should be used to explain Markovnikov addition)
16.1.1.1 electrophilic addition of steam to an alkene, catalyst
16.1.1.2 reaction of alkenes with cold dilute acidified potassium manganate(VII) to form a diol
16.1.1.3 substitution of a halogenoalkane using NaOH(aq) and heat
16.1.1.4 reduction of an aldehyde or ketone using
16.1.1.5 reduction of a carboxylic acid using
16.1.1.6 hydrolysis of an ester using dilute acid or dilute alkali and heat
16.1.2.1 the reaction with oxygen (combustion)
16.1.2.2 substitution to halogenoalkanes
16.1.2.3 the reaction with Na(s)
16.1.2.4 oxidation with acidified or acidified to:
16.1.2.5 carbonyl compounds by distillation
16.1.2.6 carboxylic acids by refluxing (primary alcohols give aldehydes which can be further oxidised to carboxylic acids, secondary alcohols give ketones, tertiary alcohols cannot be oxidised)
16.1.2.7 dehydration to an alkene, by using a heated catalyst, e.g. or a concentrated acid
16.1.2.8 formation of esters by reaction with carboxylic acids and concentrated or as catalyst as exemplified by ethanol
16.1.3.1 classify alcohols as primary, secondary and tertiary alcohols, to include examples with more than one alcohol group
16.1.3.2 state characteristic distinguishing reactions, e.g. mild oxidation with acidified K2Cr2O7, colour change from orange to green
16.1.4 deduce the presence of a group in an alcohol, , from its reaction with alkaline (aq) to form a yellow precipitate of tri-iodomethane and an ion,
16.1.5 explain the acidity of alcohols compared with water
17.1.1.1 the oxidation of primary alcohols using acidified and distillation to produce aldehydes
17.1.1.2 the oxidation of secondary alcohols using acidified or acidified and distillation to produce ketones
17.1.2.1 the reduction of aldehydes and ketones, using to produce alcohols
17.1.2.2 the reaction of aldehydes and ketones with HCN, KCN as catalyst, and heat to produce hydroxynitriles exemplified by ethanal and propanone
17.1.3 describe the mechanism of the nucleophilic addition reactions of hydrogen cyanide with aldehydes and ketones in 17.1.2(b)
17.1.4 describe the use of 2,4-dinitrophenylhydrazine (2,4-DNPH reagent) to detect the presence of carbonyl compounds
17.1.5 deduce the nature (aldehyde or ketone) of an unknown carbonyl compound from the results of simple tests (Fehling’s and Tollens’ reagents; ease of oxidation)
17.1.6 deduce the presence of a – group in an aldehyde or ketone, , from its reaction with alkaline (aq) to form a yellow precipitate of tri-iodomethane and an ion,
18.1.1.1 oxidation of primary alcohols and aldehydes with acidifiedor acidified and refluxing
18.1.1.2 hydrolysis of nitriles with dilute acid or dilute alkali followed by acidification
18.1.1.3 hydrolysis of esters with dilute acid or dilute alkali and heat followed by acidification
18.1.2.1 the redox reaction with reactive metals to produce a salt and
18.1.2.2 the neutralisation reaction with alkalis to produce a salt and
18.1.2.3 the acid–base reaction with carbonates to produce a salt
18.1.2.4 esterification with alcohols with concentrated as catalyst
18.1.2.5 reduction by form a primary alcohol
6.1.1 calculate oxidation numbers of elements in compounds and ions
6.1.2 use changes in oxidation numbers to help balance chemical equations
6.1.3 explain and use the terms redox, oxidation, reduction and disproportionation in terms of electron transfer and changes in oxidation number
6.1.4 explain and use the terms oxidising agent and reducing agent
6.1.5 use a Roman numeral to indicate the magnitude of the oxidation number of an element
7.2.1 state the names and formulae of the common acids, limited to hydrochloric acid, HC/, sulfuric acid, ethanoic acid,
7.2.10 select suitable indicators for acid-alkali titrations, given appropriate data
7.2.2 state the names and formulae of the common alkalis, limited to sodium hydroxide, NaOH, potassium hydroxide, KOH, ammonia,
7.2.3 describe the Brønsted–Lowry theory of acids and bases
7.2.4 describe strong acids and strong bases as fully dissociated in aqueous solution and weak acids and weak bases as partially dissociated in aqueous solution
7.2.5 appreciate that water has pH of 7, acid solutions pH of below 7 and alkaline solutions pH of above 7
7.2.6 explain qualitatively the differences in behaviour between strong and weak acids including the reaction with a reactive metal and difference in pH values by use of a pH meter, universal indicator or conductivity
7.2.7 understand that neutralisation reactions occur when
7.2.8 understand that salts are formed in neutralisation reactions
7.2.9 sketch the pH titration curves of titrations using combinations of strong and weak acids with strong and weak alkalis
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