Two moles of benzaldehyde and one mole of acetone under alkaline conditions using aqueous $NaOH$ after heating gives $x$ as the major product. The number of $\pi$ bonds in the product $x$ is.................

Among the following,the number of compounds which will give positive iodoform reaction is:
$(a)$ $1-$Phenylbutan$-2-$one
$(b)$ $2-$Methylbutan$-2-$ol
$(c)$ $3-$Methylbutan$-2-$ol
$(d)$ $1-$Phenylethanol
$(e)$ $3,3-$dimethylbutan$-2-$one
$(f)$ $1-$Phenylpropan$-2-$ol

In which of the following reactions is the product formed the same?

When acetaldehyde is heated with Fehling's solution,it gives a red precipitate of:

The reaction of butanal with $n$-propylmagnesium bromide gives a

The reaction that does not give benzoic acid as the major product is