14. Hydrocarbons
A section of Chemistry, 9701
Listing 10 of 313 questions
A reaction sequence based on propan-1-ol is shown. CH3CH CH2 CH3CH2CH2 CH3CH2CH2 OH Br CH3CH2C OH O CH3CH2C H O CH3CH2C CN H OH reaction 1 reaction 4 propan-1-ol reaction 5 NaCN / H+ reaction 3 reaction 2 Reactions 1 and 2 can both be carried out using the same reagents. Identify suitable reagents for reactions 1 and 2. State and explain how the reaction should be carried out to ensure that reaction2 rather than reaction1 occurs. Identify the necessary reagents and conditions for each of reactions 3 and 4. reaction 3 reaction 4 Complete the reaction mechanism for reaction 5. Include all relevant lone pairs, curly arrows, charges and partial charges. CH3CH2 C CH3CH2 CN H OH O C H NC− The product of reaction 5 exhibits stereoisomerism. Draw the two stereoisomers in the conventional way. Suggest why a mixture of the two stereoisomers is formed by reaction 5.
9701_s16_qp_22
THEORY
2016
Paper 2, Variant 2
View
P, Q and R all have the molecular formula C3H6O. They are all structural isomers of each other. P and Q each contain an oxygen atom bonded directly to a carbon atom that is sp2 hybridised. R contains an oxygen atom bonded directly to a carbon atom that is sp3 hybridised. Explain the meaning of the term structural isomers. Explain how sp2 and sp3 hybridisation can occur in carbon atoms. sp2 hybridisation sp3 hybridisation State the bond angles normally associated with each type of hybridisation in carbon atoms. sp2 sp3 R contains two different functional groups, one of which is an alkene group. R reacts with cold, dilute, acidified manganate(ions to form propane-1,2,3-triol. H HO C H OH OH C propane-1,2,3-triol H H C H Give the displayed formula of R. State the type of reaction and what you would observe when R reacts with bromine water. Draw the structure of the product formed when R reacts with bromine water. Identify the gaseous product formed when R reacts with hot, concentrated, acidifiedmanganate(ions. P and Q (C3H6O) both form an orange precipitate when reacted with 2,4-DNPH. Only Q produces a yellow precipitate when reacted with alkaline aqueous iodine. Name P and Q. P Q Identify the yellow precipitate formed by the reaction of Q with alkaline aqueous iodine. P and Q each react with hydrogen cyanide to form a single product. The product formed from P exists as a pair of optical isomers. The product formed from Q does not exhibit optical isomerism. Explain the meaning of the term optical isomers. Ethanal, CH3CHO, also reacts with hydrogen cyanide. The product of this reaction is CH3CH(OH)CN. Draw the mechanism of this reaction. Include all necessary charges, dipoles, lone pairs and curly arrows.
9701_s17_qp_21
THEORY
2017
Paper 2, Variant 1
View
Questions Discovered
313