Benzalacetone is the product of mixed aldol condensation between benzaldehyde $(C_6H_5CHO)$ and acetone $(CH_3COCH_3)$. What is its structure?

Rank the following compounds in order of increasing value of the equilibrium constant for hydration,$K_{hyd}$. (smallest value first).
$1$: Cyclobutanone
$2$: Cyclopropanone
$3$: Di-tert-butyl ketone

Identify the major product from the following reaction sequence.

Given below are two statements $:$
Statement $(I) :$ Vanillin,with the structure shown below,will react with $NaOH$ and also with Tollen's reagent.
Statement $(II) :$ Vanillin will undergo self-aldol condensation very easily.
In the light of the above statements,choose the most appropriate answer from the options given below $:$

In which of the following reactions,two products will be formed other than triphenylphosphine oxide $(Ph_3PO)$?

Which among the following aldehydes is most reactive towards nucleophilic addition reactions?