alcohols

Question 1

what are alcohols?

Answer 1

alcohols are a homologous series of organic compounds which have the hydroxyl (-OH) functional group

Question 2

what is the general formula for alcohols?

Answer 2

CnH2n+1OH

Question 3

what is methanol’s
-full structure bond
-no. of carbon atoms
-molecular formula

Answer 3

1 carbon atom
CH3OH

Question 4

what is ethanol’s
-full structure bond
-no. of carbon atoms
-molecular formula

Answer 4

2 carbon atoms
C2H5OH

Question 5

what is propanol’s
-full structure bond
-no. of carbon atoms
-molecular formula

Answer 5

3 carbon atoms
C3H7OH

Question 6

what is butanol’s
-full structure bond
-no. of carbon atoms
-molecular formula

Answer 6

4 carbon atoms
C4H9OH

Question 7

are alcohols alkalis? why?

Answer 7

alcohols are not alkalis. they do not produce OH- ions when dissolved in water

Question 8

what are the physical properties of alcohols?

Answer 8

alcohols are volatile liquids at room temperature and pressure
down the homologous series, as the molecular size increases…
solubility in water decreases
stronger intermolecular forces(boiling point increases)

Question 9

what are the chemical properties of alcohols?

Answer 9

combustion
alcohols can be used as fuel and can undergo incomplete or complete combustion
oxidation
alcohols can be oxidised by acidified potassium manganate or oxygen in air to form carboxylic acids
purple acidified potassium manganate will turn colourless if alcohol is present

Question 10

production of ethanol

Answer 10

ethanol can be produced by the fermentation of glucose
it is a process in which micro-organisms such as yeast act on carbohydrates like glucose in the absence of oxygen to produce ethanol and co2

Question 11

what are the necessary conditions for the production of ethanol?

Answer 11

37 degrees celsius
yeast
absence of oxygen

Question 12

what is the experimental set up for the production of ethanol?

Answer 12

glucose solution is mixed with yeast in a conical flask
the flask is immersed in a water bath and kept at 37 degrees celsius for a few days
a dilute aqueous solution of ethanol is produced. pure ethanol can be obtained from this mixture by fractional distillation
if temp too high, enzymes will denature
limewater serves as airlock and prevent oxygen from entering the set up. it also allows us to check whether fermentation is taking place
if co2 is produced, white ppt will form in limewater