L4

Question 1

If a sugar contains a hemiacetal what does in mean in regards to aldehydes?

Answer 1

It contains a small percentage of open chain form aldehydes

Question 2

What kind of sugar is it if it contains an open chain aldehyde form? (reducing or non reducing)

Answer 2

Reducing sugar

Question 3

What is a glycoside?

Answer 3

Cyclic acetal form of sugar

Question 4

What is a glycoside?

Answer 4

Cyclic acetal form of sugar

Question 5

What conditions are acetals stable? and what does it do to large carbohydrates?

Answer 5

Absence of H+
Stable in H2O

Stability to polysaccharides

Question 6

A glycoside in H2O without acid, is it capable of undergoing tollens reactions and why?

Answer 6

No as its a non reducing sugar and unable to undergo tollens reaction as there is no open chain form

Question 7

Can a pure acetal be oxidised into carboxylic acid directly?

Answer 7

No

Question 8

If a glycoside is in and acidified alcohol solution what does it mean in relation to bet and alpha?

Answer 8

They are in equilibrium

Question 9

How can two monosaccharides be linked together?

Answer 9

O from OH group attacks sugar 1’s carbon forming glycosidic bond

Question 10

How do you know if a sugar is reducing or not?

Answer 10

If there is a hemiacetal on the end