27 – Synthesising & Investigating Benzoic Acid (LC 2027) (Leaving Cert Chemistry): Flashcards
📚Flashcards
Practise the cards
15 cards from this deck
ShowHide
Practise the cards
15 cards from this deck
Molecular formula of benzoic acid
Molecular formula of benzoic acid
Sodium benzoate food code and use
Sodium benzoate food code and use
E211, food preservative
Three stages of benzoic acid experiment
Three stages of benzoic acid experiment
Synthesis by oxidation, recrystallisation, melting point test
Starting material for benzoic acid synthesis
Starting material for benzoic acid synthesis
Phenylmethanol (benzyl alcohol)
Oxidising agent in benzoic acid synthesis
Oxidising agent in benzoic acid synthesis
Potassium permanganate
Reaction conditions for benzoic acid synthesis
Reaction conditions for benzoic acid synthesis
Alkaline conditions
Colour change during benzoic acid synthesis
Colour change during benzoic acid synthesis
Purple to brown
Why acidify with HCl after oxidation?
Why acidify with HCl after oxidation?
Convert sodium benzoate to benzoic acid
Principle of recrystallisation
Principle of recrystallisation
Different solubilities at different temperatures
Benzoic acid solubility: hot vs cold water
Benzoic acid solubility: hot vs cold water
Very soluble in hot, slightly soluble in cold
Purpose of hot filtration in recrystallisation
Purpose of hot filtration in recrystallisation
Remove insoluble impurities
Purpose of cold filtration in recrystallisation
Purpose of cold filtration in recrystallisation
Separate pure crystals from soluble impurities
Melting point of pure benzoic acid
Melting point of pure benzoic acid
121-122°C (sharp)
What does melting point indicate?
What does melting point indicate?
Purity of sample
Filtration equipment used in synthesis
Filtration equipment used in synthesis
Buchner funnel
