Alcohols

Question 1

What catalyst is used in the dehydration of alcohols?

Answer 1

Sulfuric acid (H2SO4)

Question 2

What are the two ways alcohols are formed?

Answer 2

-Hydration of an alkene
-Fermentation

Question 3

What does biofuel mean?

Answer 3

​A fuel derived from living matter

Question 4

What is the optimum temperature for fermentation?

Answer 4

30-40°C

Question 5

What are the conditions for the hydration of alkenes?

Answer 5

conc Phosphoric acid
300°C
60atm

Question 6

What are the equations for fermentation?

Answer 6

6CO2 + 6H2O → C6H12O6 + 6O2
C6H12O6 → 2C2H5OH + 2CO2
C2H5OH + O2 → 2CO2 + 3H2O

Question 7

What are the disadvantages of biofuels?

Answer 7

-Requires alot of land to grow crops → reduces biodiversity
-Land could be used to grow food we can eat
-Engines have to be converted which is expensive

Question 8

What is a positive result for Fehlings?

Answer 8

Brick red ppt

Question 9

What is a positive result for Tollens reagent?

Answer 9

Silver mirror

Question 10

What is used to oxidise alcohols?

Answer 10

Potassium dichromate/ K2Cr2O7 / [O]

Question 11

What colour change does potassium dichromate when it reacts with 1°,2 ° & 3 ° alcohol?

Answer 11

-Primary: orange → green
-secondary: orange → green
-Tertiary: no change

Question 12

How do you form a carboxylic acid?

Answer 12

Primary alcohol with potassium dichromate under reflux (with sulfuric acid)

Question 13

How do you form an aldehyde?

Answer 13

Primary alcohol with potassium dichromate using distillation (with sulfuric acid)

Question 14

How do you form a ketone?

Answer 14

Secondary alcohols with potassium dichromate under reflux (with sulfuric acid)