The correct order of rate of reaction toward nucleophilic addition reaction for the following compounds is:
$(a)$ $p-NO_2-C_6H_4-CHO$
$(b)$ $C_6H_5-CHO$
$(c)$ $p-OMe-C_6H_4-CHO$
$(d)$ $CH_3-CO-CH_2CH_3$
$(e)$ $C_6H_5-CO-C_6H_5$

Given below are two statements:
Statement $I$: Cross aldol condensation between two different aldehydes will always produce four different products.
Statement $II$: When semicarbazide reacts with a mixture of benzaldehyde and acetophenone under optimum pH, it forms a condensation product with acetophenone only.
In the light of the above statements, choose the correct answer from the options given below:

$CaOCl_2 + H_2O \longrightarrow Ca(OH)_2 + X$
$X + CH_3CHO \longrightarrow Y$
$Y + Ca(OH)_2 \longrightarrow CHCl_3$
What is '$Y$'?

The major product formed in the following reaction is:

Which of the following compounds has the most acidic hydrogen?

Which of the following compounds gives a positive test with $2,4$-$DNP$ ($2$,$4$-dinitrophenylhydrazine)?
$(a)$ Acetone
$(b)$ Butan-$2$-one
$(c)$ Acetaldehyde
$(d)$ Formaldehyde