Investigating how the rate of hydrolysis of halogenoalkanes varies.

Because Halogens are Electronegative attaching one to a carbon atom would create a Polar Covalent Bond. Therefore the carbon atom provides the C + atom which can be attracted by a nucleophiles.

Halogenoalkanes are classified according to their structures, primary, secondary and tertiary.

In a primary halogenoalkane the halogen atom is covalently bonded to a carbon atom, which in turn has a covalent bonded to just one other carbon atom.

In a secondary halogenoalkane the halogen atom is covalently bonded to a carbon atom, which in turn has a covalent bonded to just two other carbon atom and.

In a tertiary halogenoalkane the halogen atom is covalently bonded to a carbon atom, which in turn has a covalent bonded to just three other carbon atom.

Mixing halogenoalkanes to ethanol evokes nucelophillic substitution to occur when heated, thus producing an alcohol, either Primary, Secondary or indeed tertiary alcohols are produced

A nucleophilic substitution is where the halogen atom will leave the halide ion and so the atoms replacing the halogen must process a lone pair of electrons and a covalent bond forms.

For this experiment a hydrolysis reaction will be taken place. A hydrolysis reaction involves braking covalent bonds by reacting with water.

For this experiment there will be three reactions being carried out. For each reaction Silver nitrate will be used AgNO3

Ag+ (aq) + Cl-(aq) AgCl(s)

Ag+ (aq) + Br-(aq) AgBr(s)

Ag+ (aq) + I-(aq) AgI(s)

The reactions will be monitored by the precipitations. 1-chlorobutane produces a faint white precipitate, 1-bromobutane produces a white precipitate and 1-iodobutane produces a yellow precipitate of silver iodide.

Equipment

Safety Spectacles, 6 test tubes, test tube rack, measuring cylinder,

Clamp stand, 1 stand, 1 mat, Bunsen burner, 1-chlorobutane, 1-bromobutane, 1-iodobutane, ethanol, silver nitrate

Method

. Collect equipment, stand 3 test tubes in the rack.

2. Add 3 drops of 1-chorobutanane to one test tube, then 3 drops of 1-bromobutane to another test tube and 3 drops of 1-iodobutane to the 3rd test tube.

3. Now add 2cm3 of Ethanol to each test tube.

4. Light the Bunsen burner and in the other 3 test tubes heat 2cm3 of 0.02M Silver nitrate.

5. Once silver nitrate is near boiling quickly add 2cm3 to each halogenoalkane

6. Watch test tubes and record the order of precipitates appearing and the colour of each precipitate.

Results Table

Chorobutanane,

Iodobutane

Bromobutane,

Colour of Precipitate

Precipitate is slow to form

Yellow

White

Order

Third

First

Second