intro to aldehydes and ketones

give the general eqn for the conversion of an aldehyde to a 1^o alcohol - state the conditions and whether this is oxidation or reduction:

• react w/ aq NaBH₄ - acts as reducing agent

• reduction

give the general eqn for the conversion of a ketone to a 2^o alcohol - state the conditions and whether this is oxidation or reduction:

• react w/ NaBH₄ - acts as reducing agent

• reduction

give the general eqns for the conversions to other organic compounds that may occur for a 1^o alcohol - state the conditions and whether they are oxidation or reduction reactions:

• both oxidation

• 1^o alcohol oxidised to aldehyde

• heat and distil w/ H₂SO₄ and Kr₂Cr₂O₇ - latter is the oxidising agent

• aldehyde can be oxidised further to a carboxylic acid using same reagents and heating under reflux OR heating w/ Tollen’s/Fehling’s

give the general eqn for the conversion of a 2^o alcohol to a ketone - state the conditions and whether this is oxidation or reduction:

• 2^o alcohol oxidised to ketone

• heat under reflux w/ H₂SO₄ and K₂Cr₂O₇ - latter is the oxidising agent

• oxidation - cannot be oxidised further

give the eqn for and explain the colour change when 1^o/2^o alcohols are added to acidified potassium dichromate (VI):

• orange dichromate (VI) ion is reduced to the green chromium (III) ion

• Cr₂O₇²⁻ + 14H⁺ + 6e⁻ → 2Cr³⁺ + 7H₂O