Which organic compounds are soluble in water (C1–4/5 approx.)?
Alcohols, carboxylic acids, and amines.
Which organic compounds are insoluble in water?
Alkanes, alkenes, alkynes, haloalkanes, and larger alcohols, carboxylic acids, and amines (C5 and above).
What does miscible mean?
Liquids that mix completely (no visible layers).
What does immiscible mean?
Liquids that do not mix; separate into layers.
How do amines affect litmus paper and Universal Indicator?
Turn red litmus paper blue; blue litmus stays blue. Turn green UI solution blue (basic).
How do carboxylic acids affect litmus paper and Universal Indicator?
Turn blue litmus paper red; red litmus stays red. Turn green UI solution orange (acidic).
How do alcohols affect litmus paper or Universal Indicator?
No change to red/blue litmus or green UI solution (neutral).
What happens when an alkane reacts with bromine water (Br₂)?
Slow reaction requiring UV light/heat. Orange bromine water slowly decolourises (substitution reaction).
What happens when an alkene or alkyne reacts with bromine water (Br₂)?
Fast reaction, orange bromine water rapidly decolourised (addition reaction).
What happens when an alkene reacts with acidified KMnO₄ (MnO₄⁻/H⁺)?
Purple permanganate rapidly decolourised, forming a diol (oxidation reaction).
What happens when MnO₄⁻/H⁺ reacts with something that’s not an alkene?
Brown precipitate (MnO₂) forms.
How do you test for a primary alcohol?
Warm with acidified dichromate (Cr₂O₇²⁻/H⁺) or MnO₄⁻/H⁺ and heat.
Colour change: orange → green (Cr³⁺) or purple → colourless (Mn²⁺). Type of reaction: Oxidation.
What do amines smell like?
Fishy or like something decomposing.
What do carboxylic acids smell like?
Sharp smell — e.g. ethanoic acid (vinegary), butanoic acid (rancid butter).
What happens when a carboxylic acid reacts with carbonate (CaCO₃) or hydrogen carbonate (NaHCO₃)?
Bubbles of CO₂ gas form.
Type of reaction: Acid–base / neutralisation.
What is the type of reaction when an alkane reacts with bromine water?
Substitution.
What is the type of reaction when an alkene reacts with bromine water?
Addition.
What is the type of reaction when an alkene reacts with acidified permanganate (MnO₄⁻/H⁺)?
Oxidation (forms a diol).
What is the type of reaction when a primary alcohol reacts with dichromate or permanganate under heat?
Oxidation.
What is the type of reaction when a carboxylic acid reacts with a carbonate?
Acid–base / neutralisation.
