Which of the following will not give $D.N.P.$ test?

The reaction sequence is as follows:
Benzene + $CH_3COCl$ $\xrightarrow{\text{Anhydrous } AlCl_3} (A)$ $\xrightarrow{(x)} \text{Ethylbenzene}$.
Reagent $(x)$ can be:

Given below are two statements:
Statement $I$ : Acidity of $\alpha$-hydrogens of aldehydes and ketones is responsible for Aldol reaction.
Statement $II$ : Reaction between benzaldehyde and ethanal will $NOT$ give Cross-$Aldol$ product.
In the light of above statements,choose the most appropriate answer from the options given below.

One mole of an organic compound requires $0.5$ mole of oxygen to produce an acid. The compound may be

Which is correct about vanillin?

Which of the following will give a yellow precipitate $(ppt.)$ with iodine and alkali?