The following compounds differ in respect of

Which of the following is not a polysaccharide?

Consider the following reactions:
$(i)$ $\text{Glucose} + ROH$ $\xrightarrow{\text{dry } HCl} \text{Acetal}$ $\xrightarrow{x \text{ eq. of } (CH_3CO)_2O} \text{acetyl derivative}$
$(ii)$ $\text{Glucose}$ $\xrightarrow{Ni/H_2} A$ $\xrightarrow{y \text{ eq. of } (CH_3CO)_2O} \text{acetyl derivative}$
$(iii)$ $\text{Glucose} \xrightarrow{z \text{ eq. of } (CH_3CO)_2O} \text{acetyl derivative}$
$x, y$ and $z$ in these reactions are respectively:

Which is not a reducing sugar?

Glucose and fructose are

Only two carbon atoms of glucose participate in the formation of osazone because they undergo .......