Core Practical 4

Question 1

Describe brief method of practical (hydrolysis of halogenoalkane)

Answer 1

Add ethanol + haloalkane to test tubes and put in 60’c water baths
put silver nitrate in test tube and also heat in water bath
then add silver nitrate to haloalkanes and record time taken for precip to form?

Question 2

Which haloalkane reaction is quickest and what does this mean about the bond?

Answer 2

The iodoalkane bond is weakest therefore rate of reaction quickest

Question 3

What type of reaction is this?

Answer 3

Nucleophilic substitution where water acts as nucleophile

Question 4

What causes the precipitate?

Answer 4

Ag+ with a X- halide ion

Question 5

What are the two variables?

Answer 5

either change the type of haloalkane e.g. chloro, bromo

OR the type of alkane (primary, secondary, tertiary)

Question 6

What would the expected order of reaction times for
1-bromobutane
2-bromobutane
2-bromo-2methylpropane

Answer 6

2-bromo-2methyl = fastest = tertiary

slowest=primary (1-bromobutane)

Question 7

How can you reduce the degree of uncertainty?

Answer 7

lower temperatures reduce the rate of reaction. This will make the time differences will be more pronounced producing a ​lower uncertainty​​.

Question 8

Why are water baths used?

Answer 8

To keep the temperature constant so it doesn’t affect the rate of hydrolysis