The best reagent to convert $pent-3-en-2-ol$ into $pent-3-yn-2-one$ is

What are $A, B, C$ and $D$ in the following cross-aldol condensation reaction?
$\text{Propanal} + \text{Ethanal} \xrightarrow[ii) \ \Delta]{i) \ NaOH} A + B + C + D$
(The products are the four possible $\alpha,\beta$-unsaturated aldehydes formed by self and cross-aldol condensation followed by dehydration.)

Which of the following substances will give the silver mirror test?

The product $(A)$ of the following reaction is (bromination does not occur in the benzene ring):

What are $x$ and $y$ in the following reaction sequence?

Which of the following can be used to convert $3$-methylbutan-$2$-one into isopentane?