Tests/ Experiments with Alcohols
- Created by: Dharpana
- Created on: 11-03-13 01:40
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- Tests/ Experiments with Alcohols
- Combustion
- Small Amount of Alcohol is ignited on a deflagrating spoon
- FUME CUPBOARD
- Burns with a CLEAN and COLOURLESS FLAME
- alcohol + oxygen -> carbon dioxide and water
- C2H5OH + 3(O2) -> 2(CO2) + 3(H2O)
- C2H5OH + 3(O2) -> 2(CO2) + 3(H2O)
- alcohol + oxygen -> carbon dioxide and water
- Burns with a CLEAN and COLOURLESS FLAME
- alcohol + oxygen -> carbon dioxide and water
- alcohol + oxygen -> carbon dioxide and water
- Small Amount of Alcohol is ignited on a deflagrating spoon
- Reaction with Sodium
- Add a small piece of sodium to Xcm3 a particular alcohol
- Similar to the Reaction of Sodium with WATER - but much less violent
- Alcohols and Water both contain an OH GROUP - chemically similar, therefore they react in similar ways
- i.e. both are polar
- Effervescence is seen: hydrogen gas is produced
- Sodium does NOT MELT
- alcohol + sodium -> sodium alcoxide + hydrogen gas
- alcohol + sodium -> sodium alcoxide + hydrogen gas
- Sodium does NOT MELT
- Sodium does NOT MELT
- C2H5OH + Na -> C2H5ONa + 1/2(H2)
- Alcohols and Water both contain an OH GROUP - chemically similar, therefore they react in similar ways
- Oxidation
- 1: Add some potassium dichromate VI to some dilute sulphuric acid
- acidifies the potassium dichromate - turns it orange
- 2: Add 2-3 drops alcohol
- HEAT
- 3: Add 2-3 drops sodium carbonate
- PRIMARY ALCOHOL
- orange K2CR2O7 solution turns green
- SECONDARY ALCOHOL
- a ketone is produced [C=O]
- Boil with Benedicts Solution
- NEGATIVE RESULT: solution stays dark blue
- Boil with Benedicts Solution
- a ketone is produced [C=O]
- primary and secondary alcohols are oxidised by the dichromate ion - this reduces it to green Cr3+ ions
- a ketone is produced [C=O]
- Boil with Benedicts Solution
- NEGATIVE RESULT: solution stays dark blue
- Boil with Benedicts Solution
- SECONDARY ALCOHOL
- an aldehyde is produced [CH=O]
- orange K2CR2O7 solution turns green
- SECONDARY ALCOHOL
- primary and secondary alcohols are oxidised by the dichromate ion - this reduces it to green Cr3+ ions
- SECONDARY ALCOHOL
- partial oxidation
- this can be further oxidised to a carboxylic acid
- complete oxidation
- colourless vapour & hot glass
- REFLUX/ CONC H2S04/ EXCESS Oxidising Agent (K2CR2O7)
- sour vinegar smell
- fizzing with sodium carbonate solution - acidic product
- Boil with Benedicts Solution
- NEGATIVE RESULT: solution stays dark blue
- Boil with Benedicts Solution
- fizzing with sodium carbonate solution - acidic product
- complete oxidation
- Limited Oxidising Agent (K2CR207) - PARTIAL
- NO CONDENSER
- colourless vapour produced
- glass becomes hot - EXOTHERMIC
- bitter almond smell
- no reaction - ALDEHYDE produced; not acidic
- Boil with Benedicts Solution
- POSITIVE RESULTS: colour change from dark blue to red
- orange K2CR2O7 solution turns green
- orange K2CR2O7 solution turns green
- TERTIARY ALCOHOL
- orange solution stays orange
- TERTIARY ALCOHOLS CANNOT BE OXIDISED
- orange solution stays orange
- PRIMARY ALCOHOL
- PRIMARY ALCOHOL
- an aldehyde is produced [CH=O]
- partial oxidation
- this can be further oxidised to a carboxylic acid
- complete oxidation
- colourless vapour & hot glass
- REFLUX/ CONC H2S04/ EXCESS Oxidising Agent (K2CR2O7)
- sour vinegar smell
- fizzing with sodium carbonate solution - acidic product
- Boil with Benedicts Solution
- NEGATIVE RESULT: solution stays dark blue
- Boil with Benedicts Solution
- fizzing with sodium carbonate solution - acidic product
- complete oxidation
- Limited Oxidising Agent (K2CR207) - PARTIAL
- NO CONDENSER
- colourless vapour produced
- glass becomes hot - EXOTHERMIC
- bitter almond smell
- no reaction - ALDEHYDE produced; not acidic
- Boil with Benedicts Solution
- POSITIVE RESULTS: colour change from dark blue to red
- an aldehyde is produced [CH=O]
- TERTIARY ALCOHOL
- orange solution stays orange
- TERTIARY ALCOHOLS CANNOT BE OXIDISED
- orange solution stays orange
- temperature rises - solutions fizzes
- 1: Add some potassium dichromate VI to some dilute sulphuric acid
- Halogenation
- Chlorination
- Substitution Reaction
- Bromination
- Alcohol is heated under reflux with (solid) potassium bromide and 50% sulphuric acid
- 1: a hydrogen bromide is produced
- from dissociated H+ and Br- ions
- 2: hydrogen bromide reacts with alcohol to form bromoalkane
- KBr +H2SO4 -> KHSO4 + HBr
- potassium bromide + sulphuric acid -> potassium bisulphate + hydrogen bromide
- KBr +H2SO4 -> KHSO4 + HBr
- CONCENTRATED H2SO4 will oxidise the halide and instead produce bromine/iodine and sulphur
- 1: damp red phosphorus and iodine produce phosphorus triiodide
- 2: phosphorus triiodide reacts with an alcohol to form an iodoalkane
- C2H5OH + PI3 -> 3(CH3CH2I) + H3PO3
- ethanol + phosphorus triiodide -> iodoethane + phosphoric acid
- 2P + 3(I2) -> 2(PI3)
- phosphorus + iodine -> phosphorus triiodide
- 2P + 3(I2) -> 2(PI3)
- HEAT
- 2: phosphorus triiodide reacts with an alcohol to form an iodoalkane
- 1: damp red phosphorus and iodine produce phosphorus triiodide
- HEAT & REFLUX
- 1: a hydrogen bromide is produced
- Alcohol is heated under reflux with (solid) potassium bromide and 50% sulphuric acid
- Iodination
- 1: damp red phosphorus and iodine produce phosphorus triiodide
- 2: phosphorus triiodide reacts with an alcohol to form an iodoalkane
- C2H5OH + PI3 -> 3(CH3CH2I) + H3PO3
- ethanol + phosphorus triiodide -> iodoethane + phosphoric acid
- phosphorus + iodine -> phosphorus triiodide
- HEAT
- 2: phosphorus triiodide reacts with an alcohol to form an iodoalkane
- 1: damp red phosphorus and iodine produce phosphorus triiodide
- Combustion
- HEAT & REFLUX
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