Given below are two statements. One is labelled as Assertion (A) and the other is labelled as reason (R). 

Benzaldehyde reacts with formaldehyde in the presence of alkali to form Benzyl alcohol and sodium formate.

This is an example of  crossed cannizaro reaction. Benzaldehyde gives this reaction as it is not having alpha hydrogen atom. Benzaldehyde is reduced to benzyl alcohol and formaldehyde is oxidized to sodium formate.

Formaldehyde is more reactive than aromatic aldehydes in nucleophilic addition reactions. This is due to electron-donating resonance effect of aromatic ring which makes carbonyl carbon less electrophilic.