This question is about the preparation of hexan-2-ol - AQA - A-Level Chemistry - Question 5 - 2022 - Paper 2
Question 5
This question is about the preparation of hexan-2-ol.
Hexan-2-ol does not mix with water and has a boiling point of 140 °C.
Hexan-2-ol can be prepared from hex-1-en... show full transcript
Worked Solution & Example Answer:This question is about the preparation of hexan-2-ol - AQA - A-Level Chemistry - Question 5 - 2022 - Paper 2
Step 1
Suggest, with a reason, one other appropriate safety precaution for this experiment.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Use a fume cupboard to prevent inhalation of harmful vapors. This is important as phosphoric acid is corrosive and inhaling its fumes can be hazardous.
Step 2
Give a reason for adding the distilled water in steps c and f.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The distilled water is added to dissolve any soluble impurities and help in the separation of hexan-2-ol from the aqueous layer.
Step 3
Give a reason for adding anhydrous magnesium sulfate in step h.
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Anhydrous magnesium sulfate is added to remove any water from the organic layer, ensuring that the distillate is dry.
Step 4
Complete and label the diagram of the apparatus used to filter the mixture under reduced pressure in step i.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The diagram should include a vacuum pump connected to a sidearm flask or Buchner funnel with filter paper to collect the distillate, labeled appropriately.
Step 5
Identify the most likely organic impurity, other than hex-1-ene, in the distillate collected in step j.
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The most likely organic impurity is hexan-3-ol.
Step 6
Suggest one reason why it could be difficult to remove this impurity.
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
It is likely to have a similar boiling point to hexan-2-ol, making separation by distillation less effective.
Step 7
Calculate the mass, in g, of hexan-2-ol formed from 11.0 cm³ of hex-1-ene if the yield is 31.0%.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The mass of hex-1-ene can be calculated using the density:
Mass = Volume × Density = 11.0 cm³ × 0.678 g/cm³ = 7.458 g.
If the yield is 31.0%, then the mass of hexan-2-ol = 7.458 g × 0.31 = 2.31 g.
Thus, the answer is 2.3 g when rounded to one decimal place.
