Chemical properties of Aldehydes and Ketones Reactions common to both Aldehydes and Ketones The difference between an Aldehyde and a Ketone is the position of the C=O (Carbonyl group). Aldehyde – always on a carbon at the end of the chain Ketone – Always

Chemical properties of Aldehydes and Ketones Reactions common to both Aldehydes and Ketones The difference between an Aldehyde and a Ketone is the position of the C=O (Carbonyl group). Aldehyde – always on a carbon at the end of the chain Ketone – Always on a carbon at middle carbon of the chain 1. BOTH Aldehydes and Ketones can be reduced Aldehyde reduced to Primary Alcohol Reducing agent = Sodium tetrahydroborate III (NaBH4) Ketone reduced to Secondary Alcohol Reduction Oxidisatio n Gain of ElectronsLoss of Electrons H O H3C C H + 2[H] H3C C OH H True for all secondary alcohols Carbonyl + 2[H] ─(NaBH4) Alcohol CH3CH2CHO + 2[H] CH3CH2CH2OH Propanal + NaBH4 Propan-1-ol CH3COCH3 +2[H] CH3CH(OH)CH3 Propanone + NaBH4 Propan-2-ol 2. BOTH Aldehydes and Ketones undergo nucleophilic substitution using HCN Def. A nuclophile is an electron pair donor E.g. NH3 – 1 lone pair H2O – 2 lone pairs OH– – 3 lone pairs Cl– – 4 lone pairs Therefore nucleophiles attack E.g. Cδ+=Oδ– 1 Due to a difference in electronegativity the O is electronegative than the C so attracts the electronpair more strongly