Paraldehyde is a trimer of which of the following?

Mandelonitrile is obtained by the reaction between hydrogen cyanide and

The number of correct reaction$(s)$ among the following is $\qquad$

To carry out the following conversion,arrange the reagents in the correct order:
$O_3/Zn$ $(1)$
$EtONa/EtOH/\Delta$ $(2)$
$NaOCl$ $(3)$
$H^{+}$ $(4)$

Which of the following will not give the Cannizzaro reaction?

The product obtained in the following transformation is: