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Identification of an organic unknown

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Introduction

Identification of an organic unknown Aim In this piece of coursework I will be outlining a sequence of simple chemical tests to use to identify 8 different functional groups. These functional groups I will be finding are, Alkene, primary alcohol, tertiary alcohol, aldehyde, ketone, carboxylic acid, ester and phenol. I will be explaining the tests, the observations and the safety of each test/functional group. Wet Tests Bromine water In the presence of an Alkene, the bromine water will turn the unknown from orange to colourless. C2H4(L) + Br2(L) C2H4Br2(L) In the presence of a phenol group, a white precipitate will be formed when bromine water is added.7 Phenol(L) + 3Br2(L) 2, 4, 6-tribromophenol(L) + 3HBr(L) Principal hazards Bromine vapour is released from bromine water solutions when they are open to the air. This vapour is harmful if inhaled. Bromine water is harmful if you swallow it and can cause eye damage if splashed into the eyes. Prolonged contact with the skin may lead to burns. Safe handling Wear safety glasses. Work in a well ventilated area. Do not leave bromine water in the open laboratory, unless the solution is covered to prevent vaporization of bromine. Emergency Eye contact: Immediately flush the eye with water. If irritation persists, call for medical help. ...read more.

Middle

This is not likely to be harmful, nor will it be permanent, but may be unsightly. There is a small risk of forming explosive fulminating silver, if Tollen's reagent is left unused for a period of time. To avoid this, neutralise unused reagent with a little nitric acid and discard. Safe handling Wear safety glasses. Avoid skin contact. Emergency Eye contact: Immediately flush the eye with water. If irritation persists, call for medical help. Skin contact: Wash off immediately with soap and water. If swallowed: Call for medical help if the amount swallowed is not trivial. Disposal Small amounts can be neutralised with nitric acid (test with pH paper) and then flushed down the sink if local rules permit. Do not store unwanted reagent for long periods. Protective equipment Safety glasses. 3 Acidified potassium dichromate (VI) Strong oxidising agent. Distil organic unknown with potassium dichromate (VI). If colour change happens from orange to green, the functional group has allowed the primary alcohol in the unknown to be oxidised. 4 Principal hazards Potassium dichromate is toxic if swallowed, inhaled or absorbed through the skin. It is corrosive and may produce severe eye damage. Chromium (VI) compounds are carcinogens. Potassium dichromate may act as a sensitizer. This material is a strong oxidizing agent and reacts vigorously or explosively with a wide variety of reducing agents. ...read more.

Conclusion

Safe handling Wear safety glasses. It is important that you do not inhale phosphorus pentachloride, so work in a well-ventilated area, preferably using a fume cupboard. Clean up any spills immediately. Emergency Eye contact: Immediately flush the eye with water. If irritation persists, call for medical help. Skin contact: Wash off immediately with water; seek first aid if the skin appears red or damaged. If swallowed of inhaled: Call for immediate medical help. Disposal Store, properly labelled, for later disposal as solid waste or destruction. Protective equipment Safety glasses. 6 Sodium Carbonate Sodium carbonate added to an acid will neutralize the acid, and form carbonic acid, which is not stable and so decomposes to form CO2 which is then given off. The overall reaction is: Na2CO3 + 2HCl ---> 2Na+ + 2Cl- + H2O + CO2 Adding sodium carbonate to an ester creates a fruity smell. No observant change formed. Acid + alcohol ester + water Principal hazards ** Sodium carbonate powder may irritate the lungs if you breathe it in. Safe handling Wear safety glasses if required by local rules. Emergency Eye contact: Immediately flush the eye with water. If irritation persists, call for medical help. Skin contact: Wash off with water. If swallowed: Call for medical help if the amount swallowed is large. Disposal Small amounts of sodium carbonate can be flushed down the sink unless local rules prohibit this. Protective equipment Safety glasses if required. ...read more.

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