Which of the following gives Fehling's solution test?

Which of the following compounds is most reactive towards nucleophilic attack on the carbonyl group?

The above conversion can be achieved by:

The product of the following reaction is:
$Ph-CO-CH_3 \xrightarrow[{(ii)\,\Delta }]{{(i)\,aq.\,K_2CO_3}}$ Product

The correct order of reactivity of $CH_3CHO$,$C_2H_5COCH_3$,and $CH_3COCH_3$ towards nucleophilic addition is:

$CH_3CHO + HCN$ $\xrightarrow{\text{H}^+} CH_3CH(OH)CN$ $\xrightarrow{\text{H}_3\text{O}^+} CH_3CH(OH)COOH$. In the above reaction,a chiral center is generated. What will be the nature of the resulting acid?