• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

identifcation of and organic unknown

Extracts from this document...


Identification of an organic unknown Plan Introduction In this investigation I will get a number of unknown organic compounds to which I have to identify using a number of simple chemical tests. The flow-chart below shows these simple tests that I will use to identify the functional groups of the unknowns. General safety procedures Always wear gloves and goggles when handling any unknown because some materials could be corrosive or an irritant. Be careful when disposing organic materials insure there is an organic waste beaker or bucket available. 1. Test unknown with acidified potassium manganate. THEROY: Manganate (VII) ions are a strong oxidising agent, and in the first instance oxidise ethene to ethane-1,2-diol causing the colour change from purple to colourless. The equation is as follows; C2H4 + H2O + {O} C2H6O2 EQUITMENT: pipettes, Test tube, Beaker of warm water. SAFETY: follow general safety procedures. PROCEDURE: Add 1cm3 of potassium manganate to a test tube also add 1cm3 of sulphuric acid to the test tube and also add a few drops of the unknown, final place the test tube in a beaker of warm water. ...read more.


SAFETY: always follow general safety procedures, 2,4-DNPH is explosive and toxic and ethanol is extremely flammable, so take extra care when appropriate and ensure Bunsen burners are switched off in the presence of any flammable chemical. PROCEDURE: To 1cm� of 2,4-dinitrophenylhydrazine solution and 1cm� of ethanol, add several drops of the carbonyl, ester or alcohol unknown via pipette, Heat with a water bath if necessary. OBSERVATIONS: A colour change to orange/yellow indicates the presence of a carbonyl group, which will be an aldehyde or a ketone. No colour change indicates that it is an alcohol, or ester. 5. Test unknown with tollens reagent THEROY: Aldehydes are easily oxidised to acids. Ketones cannot be oxidised, as there is no place for the oxygen from the oxidising agent. Tollens reagent consists of silver nitrate and ammonia to form the complex ion {Ag (NH3)2} this is reduced to silver in the reaction with the aldehyde forming a silver mirror. EQUIPMENT: Test tube Pipette Silver nitrate solution Sodium hydroxide solution Ammonia solution Water Bath SAFETY: Follow general safety procedures and silver nitrate solution, sodium hydroxide solution and ammonia solution are all corrosive so handle with care. ...read more.


PROCEDURE: add equal amounts of HCL and ZnCl2 to a test tube then add several drops of the alcohol and ester unknown and shake gently. OBSERVATIONS: no change indicates an ester; cloudy very quickly indicates a tertiary alcohol. 8. Confirmation of carboxylic acid with addition of base THEROY: Because of their enhanced acidity, carboxylic acids react with bases to form ionic salts, as shown in the following equation. RCO2H + NaHCO3 RCO2 (-) Na (+) + CO2 + H2O EQUITMENT: Pipette test tube NaHCO3 SAFTY: Take care when handling acids and bases as irritation to the skin can be caused, always follow general safety procedures. PROCEDURE: Add equal amounts of unknown with the NaHCO3 into a test tube using a pipette and shake gently. OBSERVATIONS: after a few seconds and salt precipitate should start to form, confirming the unknown to be a carboxylic acid. 9. Confirmation of ester by hydrolysis THEROY: Hydrolysis is simply a reaction with water, the hydrolysis of an ester produces an alcohol and a carboxylic acid the reaction is in equilibrium as shown below EQUITMENT: Test tube Pipette HCl Water SAFETY: follow general safety procedure, handle chemicals with care. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Organic Chemistry section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Organic Chemistry essays

  1. Marked by a teacher

    Reactions of aldehydes and ketones. The purpose of this experiment is to compare ...

    5 star(s)

    Tollens' reagent 18. Ammonia solution had a pungent smell. 19. The reaction mixture turned dirty green after the reaction. 20. For ethanal, there was silver mirror formed. 21. For propanone, there was no observation. Part 4 Iodoform test 22.

  2. Identification of an Unknown Organic Compound

    If the test is negative, the unknown compound is confirmed to be a secondary Alcohol. But note that the unknown compound cannot be a secondary Alcohol in context of this experiment. Safety and Hazards: * Tollen's reagent is corrosive. If there's a skin contact, the area could become black in colour over couple days.

  1. Find the enthalpy change of combustion of a number of alcohol's' so that you ...

    causing all the energy from the fuel not to be transferred to the water. I could improve this by using a bomb calorimeter. These have a stirring system, which is done automatically ensuring uniform heat flow, which means it reduces the amount of heat loss.

  2. The aim of this experiment is to produce Aspirin. This is an estrification in ...

    Mr (NaOH) = 23 + 16 + 1 = 40g 1 mol dm of NaOH = 40g 1.0 mol dm of NaOH = 40 4 = 10g To make 1000cm3 of a 1.0 mol dm-3 solution of sodium hydroxide you would need 40g of the solid.

  1. The aim of this experiment is to investigate the enthalpy change of combustion for ...

    The alcohol spread out and its surface area increased which may have effected the results, the alcohol was also not contained completely and would have been able to evaporate quite easily. The volume of water used was also too large for the small amount of alcohol being combusted, and there was no real notable increase.

  2. Esterfication. he purpose of this lab is to achieve a specific odour through ...

    Esters are also insoluble in water because they are non-polar while water is polar, not allowing one to dissolve in the other. Apparatus: - beaker - hot plate - thermometer - concentrated H2SO4 - alcohol (methanol, ethanol, 1-propanol, 1-butanol, 2-butanol, i-butanol, t-butanol, 1- pentanol, i-pentanol and octanol)

  1. F336- aspirin individual Investigation

    Analytical methods Thin layer chromatography (TLC) Chromatographic techniques are used extensively in the chemistry organic laboratory for routine analysis. Thin layer chromatography (TLC) can be used to determine the purity of a compound, to analyze the composition of a mixture or to follow the progress of a reaction.


    The apparatus shown in Fig. 1 was set up. 2. 2 cm3 of ethanol was poured into each of four test-tubes and with the letters A to D marked. 3. 3-4 drops of 1-chlorobutane were added to A, 3-4 drops of 1-bromobutane were added to B, 3-4 drops of 1-iodobutane

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work