Students write equations and Unit 4 Q6d and 6e The reduction of Outline the nucleophilic mechanisms with NaBH4 and HCN aldehydes and ketones addition mechanism for for a variety of aldehydes and January 2002 with including reduction reactions with ketones. Unit 4 Q6a mechanism. (the nucleophile should be shown as H–). Students use Molymod models to June 2002 The reaction of show how a racemic mixture is Unit 4 Q5b aldehydes and ketones overall equations for formed when ethanal reacts with with KCN then acid, the formation of HCN (students could make including mechanism. hydroxynitriles using HCN animation to demonstrate this principle). Outline the nucleophilic addition mechanism for the Practical activities: reaction with KCN followed Test-tube reactions of Tollens’ by dilute acid. reagent and Fehling’s solution to distinguish between aldehydes and Explain why nucleophilic ketones. addition reactions of KCN, Reduction of benzil with NaBH4 followed by dilute acid, can produce a mixture of enantiomers. Know the hazards of KCN 3.3.10 2.4 Use thermochemical Students work out the molecular June 2011 Kekule’s dream: Aromatic chemistry. evidence from enthalpies formula of benzene from Unit 4 Q8a and 8b of hydrogenation to percentage by mass data and 3.3.10.1 account for the extra attempt to draw structures of C6H6 January 2004 Molymod model of benzene to Bonding. delocalisation stability. (non-cyclic and cyclic). Unit 4 Q7a show delocalisation and the pi bond. January 2012
The reduction of aldehydes and ketones with including mechanism. The reaction of aldehydes and ketones with KCN then acid, including mechanism. Outline the nucleophilic addition mechanism for reduction reactions with (the nucleophile should be shown as H–). overall equations for the formation of hydroxynitriles using HCN Outline the nucleophilic addition mechanism for the reaction with KCN followed by dilute acid. Explain why nucleophilic addition reactions of KCN, followed by dilute acid, can produce a mixture of enantiomers. Know the hazards of KCN Students write equations and mechanisms with NaBH4 and HCN for a variety of aldehydes and ketones. Students use Molymod models to show how a racemic mixture is formed when ethanal reacts with HCN (students could make animation to demonstrate this principle). Practical activities: Test-tube reactions of Tollens’ reagent and Fehling’s solution to distinguish between aldehydes and ketones. Reduction of benzil with NaBH4 Unit 4 Q6d and 6e January 2002 Unit 4 Q6a June 2002 Unit 4 Q5b 3.3.10 Aromatic chemistry. 3.3.10.1 Bonding. 2.4 Use thermochemical evidence from enthalpies of hydrogenation to account for the extra delocalisation stability. Students work out the molecular formula of benzene from percentage by mass data and attempt to draw structures of C6H6 (non-cyclic and cyclic). June 2011 Unit 4 Q8a and 8b January 2004 Unit 4 Q7a January 2012 Kekule’s dream: Molymod model of benzene to show delocalisation and the pi bond.
AQA-7405-B-SOW.DOCX