Chemistry core practical 4
暂无描述。系统推荐的高质量记忆内容，适合每天坚持背诵学习。
卡片预览 (13 张)
Aim
To investigate the relative rates of hydrolysis comparing chloroalkanes, bromoalkanes and iodoalkanes
Water bath
Set up a water bath to 50°c
Preparing halogenoalkanes
Fill 3 test tubes with 5 drops of different halogenoalkanes in each Place bung on top loosely
Preparing silver nitrate solution
Pour 5cm3 silver nitrate solution into 3 separate test tubes
Controlling for temperature
Place all 6 test tubes into 50°c water bath and wait until it reaches 50°c
Measuring rate of hydrolysis
Add silver nitrate solution to one halogenoalkane and time how long it takes for a precipitate to be formed Repeat for other halogenoalkanes
What precipitate is formed when adding silver nitrate?
A silver halide eg silver chloride Which halogen had been substituted with OH from water to form this silver halide
What is acting as the nucleophile (electron pair donor) to hydrolyse the halogenoalkanes?
Water in the silver nitrate solution
Why use ethanol?
To dissolve halogenoalkanes so they can react with water
Why can water act as a nucleophile?
Contains a lone pair of electrons on oxygen a to be donated
Why is water used as a nucleophile here and not hydroxide compound?
Because white precipitate formed instantly = not long enough to time to record
What precipitate is formed fastest in terms of halogen atom?
Silver iodide because the carbon-iodine bond is the weakest due to longest bond length so faster rate of hydrolysis
What precipitate is formed fastest in terms of primary, secondary, tertiary halogenoalkane?
Tertiary