(a(i))[1]
Calcium hydroxide is put into the fermentation tanks so that the production of lactic acid does not slow down. Why might high acidity reduce the effectiveness of the enzymes?
(a(ii))[2]
The structure of lactic acid is shown. What type of reaction occurs in this polymerisation?
(b)[1]
Lactic acid has two stereoisomeric forms. Draw the other form in the box.
(c(i))
Explain why PLA would not be a suitable packaging material for foods preserved in vinegar.
(c(ii))[2]
PLA containers are not used for hot drinks. Suggest why.
(d(i))
Draw a section of the co-polymer that shows one repeat unit.
(d(ii))
Suggest what type(s) of bonding will act between chains of this co-polymer, indicating the groups involved.
(d(iii))
Suggest one property in which the co-polymer is different from PLA.