Which reagent is used to distinguish between acetaldehyde and acetophenone?

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

$CH_3CH=CHCHO$ is oxidized to $CH_3CH=CHCOOH$ using

Consider the following chemical reaction.
$CH \equiv CH \xrightarrow[{(2) CO, HCl, AlCl_3}]{{(1) Red hot Fe tube, 873 K}} \text{Product}$
The number of $sp^{2}$ hybridized carbon atom$(s)$ present in the product is ..........

$CH_3-CHO \xrightarrow{dil. OH^{-} / \Delta}$ Major product formed in the above reaction is:

Which of the following will be dehydrated most readily in alkaline medium?