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

hydrolysis of halogenoalkanes

Extracts from this document...

Introduction

Hydrolysis of Halogenoalkanes In this piece of coursework I aim to investigate the reactivity of three halogenoalkanes. By doing this it allows me to see which halogenoalkane is the most reactive and which is the least reactive. Halogenoalkanes have an alkane skeleton with one or more halogen atoms in place of hydrogen atoms. The general formula of a halogenoalkane with a single halogen atom is Cn + H2n+1X, where X is the halogen. The three halogenoalkanes that I will be testing are: 1- chlorobutane 1- bromobutane 1- iodobutane As you can see above all the halogens are primary halogens indicated by the number 1. This is where the halogen is at the end of the chain, by keeping all the halogenoalkanes as primary ones it becomes a fairer a test as the halogen is situated in the same place in each. This is because reactions may vary due to the halogen not being in the same place therefore results from the experiments taken out may not necessarily be those which are relevant to the objective of the experiment. ...read more.

Middle

There is also a difference in electronegativities between a Carbon-Halogen bonds where the halogen is more electronegative. This also makes this bond polar meaning the halogen has a slightly negative charge and the carbon has a slightly positive charge. Due to this polarity the electron deficient carbon atom is attacked by the electron-rich species which in this case is the nucleophile hydroxide ion. As the hydroxide ion and carbon atom are attracted to each other, the carbon-halogen bond breaks so halogen leaves as a halide ion. As halogenoalkanes are insoluble in water the reaction will have to carried out in the presence of ethanol, which acts as a solvent. This creates a hydrolysis reaction. There are no colour changes during this reaction as halogenoalkanes are covalently bonded; they give no precipitate of silver halide. Therefore silver nitrate will be used, and gradually the halogen can be detected determined by the colour of the precipitate. If the precipitate is white then this means that chlorine is present, if cream bromine is the halogen present and finally if yellow it is iodine which is present in the halogenoalkane. ...read more.

Conclusion

Halogen Electronegativity Value Chlorine 3.0 Bromine 2.8 Iodine 2.5 This means that the polarity of the C-Cl bond is more polar than C-Br and finally the C-I is the least polar bond. From this the reactivity of the halogens involved is as follows; Cl>Br>I. Bond enthalpy however predicts that the reverse will be true where the iodo-compound will be the most reactive. Below is a table showing the bond enthalpies of the carbon-halogen bond. Bond Bond enthalpy/ kJmol?� Carbon-Chlorine 346 Carbon-Bromine 290 Carbon-Iodine 228 Bond enthalpy which is the energy required to break a bond shows us that iodo-compound will have the weakest bond while the bromo-compounds have stronger bonds and then finally chloro-compounds have the strongest bonds. This is due to the atomic radius of the atoms where iodine is the biggest and chlorine has the smallest atomic radius. The outermost electrons feel less of the nuclear charge as the atoms have a larger atomic radius; this means that it easier for other atoms to react with the electrons of the bigger atom. From this the reactivity of the carbon-halogen bond is as follows; C-I>C-Br>C-Cl. Bond enthalpy governs the rate of reactions of the halogenoalkanes. ...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 Physical 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 Physical Chemistry essays

  1. Alkaloids are the most diverse group of secondary metabolites and over 5000 compounds are ...

    was present, and the structure of morphine and codeine were first proposed in 1923 and 1925 respectively by Robinson and Gulland. Synthesis of morphine was carried out in 1956 by Gates. Atropine on the other hand, is not generally a natural product but arises through racemisation of (-)-hyoscyamine (see (a)

  2. Investigating the Rate of the Reaction between Bromide and Bromate Ions in Acid Solution

    A slight difference in concentration of a reactant could lead to a difference in the rate. This could have been particularly noticeable if the concentration of hydrogen ions was not as it should have been, since this would have had a disproportionate effect on the rate, as shown by the rate equation that I derived.

  1. Double Displacement Reactions

    Pb(NO3)2(aq) + Cu(NO3)2(aq) --> Pb(NO3)2(aq) + Cu(NO3)2(aq) IX. Conclusion and Evaluation: My hypothesis, "If the compound is containing mettle and is added to a compound that is also containing mettle. The two mettles will change places and then something in the equation will precipitate out of the solution.

  2. The Determination of rate equation

    rate equation through the process of timing the reaction rate are not very accurate, the reason behind this is that when analysing the graphs and trying to determine the rate equation by analysing the graph I could only work out the order of reaction for one graph; the graph which

  1. Investigating how concentration affects rate of reaction

    This suggests that when there is less reactant molecules it is less likely that there will be a collision between two particles. If molecules are not colliding as often then reactions between molecules will also occur less often. This means that the reaction occurs at a much slower rate.

  2. Open-Book Paper: Radioactive Decay, Nuclear Fission and Nuclear Fusion

    As detailed above, a tokamak is used, this has some problems. The plasma still touches the bottom of the chamber, and where it does this; hydrogen reacts with the walls forming hydrocarbon radicals. These can form a film, which flakes away into the plasma, affecting performance21.

  1. detremining the rate equation

    * 100 cm3 conical flask this where the reaction takes place ( where the reactants will be mixed) * a black cross drawn on a white tile- this will be used to determine the end of the reaction when it disappears.

  2. Individual investigation - Reaction to be studied Rate of reaction between propanone and ...

    So I repeat the experiment with small concentration (0.005moldm-3) of sodium thiosufate (VI) which will give me high titre volume with low percentage error. Reducing the concentration of sodium thiosulfate (VI) to 005moldm-3. > Observations: Same observation as before.

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