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

reaction of halogenoalkanes

Extracts from this document...

Introduction

Rates of reaction of halogenoalkanes Introduction In my experiment I will be comparing how the rate of displacement of the halide ion in a nucleophilic substitution reaction varies with respect to the C-X bond(where X is a halogen- either Cl, Br, or I). Firstly, I will show how nucleophilic substitution works with the equation below: C2H5Br + H2O � C2H5OH + HBr Bromoethane water ethanol hydrogen bromide In the above equation the OH� from the water acts as a nucleophile. Nucleophiles have a spare pair of electrons and so are attracted to the positive carbon atom in the bromoethane: H H ? ? H-C-C-Br OH� (you can also see that the bromoethane is a primary ? ? structure as it has two hydrogen atoms bonded to the H H main carbon atom) This nucleophile forms an intermediate and so the carbon has 5 bonds (10 electrons) in its outermost shell. H H OH ? ...read more.

Middle

However if the polarity of the bonds is considered, the halogens are more electronegative than carbon so the polarity will be C - X� (where X is a halogen). These bonds are attacked by nucleophiles (as in introduction) at the carbon atom. As you go down the group of halogens, their electro negativity decreases (essential as chemistry for OCR). This makes the polarity of the bonds decrease as you go down the group because the difference in charge between the C and X decreases. However, this would predict that Chlorine is the most reactive as it is the most polar, but I predict that iodine is the most reactive because of bond enthalpy, that iodo-compounds have the weakest bonds (essential AS chem. OCR pg 115) Apparatus * Three test tubes and test tube rack * Ethanol (as a solvent) * Water (to provide OH ion) * Measuring cylinder * Safety goggles * Chloroethane, bromoethane and iodoethane( these are primary substrates and good for substitution reactions, if I was to do an elimination I would use tertiary structures) ...read more.

Conclusion

(essential as chemistry for OCR section 6.2.4) * 1cm� of 0.05 mol dm� silver nitrate solution is added to each of the test tubes, a bung put on each and the tubes are shaken and the time taken for the precipitate to form can be recorded using a stop watch. * When the precipitate forms, stop timing. * The precipitate that forms first will have the fastest reaction because, firstly the halogenoalkane reacts with the nucleophile to leave an alcohol (in this case, ethanol) and the halide ions, which will then form precipitates with the aqueous silver nitrate. Precautions Safety glasses must be worn to prevent any mixtures from entering the eye. Care must be taken using ethanol as it is flammable so no naked flames. (Although, the experiment doesn't require heat). Stools and bags must be under desks to prevent tripping up whilst carrying chemicals and hair tied back as to prevent it obstructing sight and getting in chemicals. A lab coat is also essential to prevent spillages onto clothing. ?? ?? ?? ?? Holly Wilkinson 08/05/08 1 ...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. The aim of this experiment is to investigate the enthalpy change of combustion for ...

    A value of -1130.656KJ/mol was recorded however the line of best fit suggests a value of -1360KJ/mol. Performing three repeat readings of each alcohol and taking the overall average may have eliminated this result.

  2. Rates of Halogenoalkanes

    As 7 group is descended, the size of the halogen atom increases, i.e. iodine is a much larger atom than chlorine. The larger the halogen atom is the less the bond overlap with the carbon atom, resulting in a longer C-X bond.

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

    A stopper was added to the flask and inverted several times to help mix the contents. Method Once the solution was prepared the next procedure conducted was the titration. In this method measurements were taken carefully in order to accurately obtain precise results in the titration.

  2. The aim of this experiment is to obtain the rate equation for the reaction ...

    4 0 [Propanone] /mol dm-3 0.4 0.8 1.2 0.4 0.4 0.4 0.4 [I2]/ mol dm-3 0.004 0.004 0.004 0.008 0.002 0.004 0.004 [H+]/mol dm-3 0.4 0.4 0.4 0.4 0.4 0.8 1.2 13. The propanone solution was poured into the solution in the boiling tube and the stopwatch was started immediately.

  1. Enzyme catalysed decomposition of hydrogen peroxide

    and prevents any oxygen from being released out of the conical flask. To prevent any oxygen from being released out of the conical flask. 1x 100 cm3 Gas syringe Used to draw a volume of a gas from the conical flask and measures the volume of oxygen given off in a reaction.

  2. Comprehensive and Detailed Chemistry notes

    allotropes O2 and O3 and account for them on the basis of molecular structure and bonding Properties gaseous oxygen gaseous ozone Explanation colour colourless blue - boiling point -183�C -111�C The boiling point of diatomic oxygen is lower than that of the ozone as diatomic oxygen has a lower molecular mass requiring less energy in the boiling process.

  1. Planning Coursework - Investigation of rate of hydrolysis of halogenoalkanes

    Control variable There are several factors that affect the rate of precipitate forming and they are: 1) Concentration of silver nitrate used 2) Concentration of halogenoalkanes used 3) Volume of ethanol used All these factors have to be kept constant in order to prove a fair test and five accurate and reliable results.

  2. HYDROLYSIS OF ORGANIC HALOGEN COMPOUNDS

    The polarization of the C-X bond makes the electron deficient carbon atom susceptible to attack by a electron rich nucleophile. Halogen atom can form a stable leaving ion. The following are the fair tests: Controlled variables Independent variable Dependent variable * Temperature * Drops of Haloalkane/Halobenzene added * Concentration and

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