Formalin is the commercial name of

The reaction of $3$-bromobenzaldehyde with concentrated $NaOH$ $(50\, \%)$ yields which of the following products?

In the Claisen$-$Schmidt reaction to prepare dibenzalacetone from $5.3 \ g$ benzaldehyde,a total of $3.51 \ g$ of product was obtained. The percentage yield in this reaction was $......... \%.$

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.

$Ph-CH_2-CN \xrightarrow[(1) EtONa]{(2) CH_3-COCl, (3) H_3O^{\oplus}/\Delta} (P)$; Product $(P)$ of the reaction will be

Which one of the following reactions is a method for the conversion of a ketone into a hydrocarbon?