An important reaction of acetone is autocondensation in the presence of concentrated sulphuric acid to give the aromatic compound:

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.)

Identify the product formed in the following reaction: $CH_3-CH=CH-CH_2-CHO \xrightarrow[(ii) \ H_3O^{+}]{(i) \ LiAlH_4} \text{Product}$

Identify product $B$ in the following reaction: $\text{Propanone}$ $\xrightarrow{\text{Ba(OH)}_2} A$ $\xrightarrow{\Delta, -\text{H}_2\text{O}} B$

What is meant by the following terms? Give an example of the reaction in each case.
$(i)$ Cyanohydrin
$(ii)$ Acetal
$(iii)$ Semicarbazone
$(iv)$ Aldol
$(v)$ Hemiacetal
$(vi)$ Oxime
$(vii)$ Ketal
$(viii)$ Imine
$(ix)$ $2,4-DNP$ derivative
$(x)$ Schiff's base

In the reaction sequence $2CH_3CHO$ $\xrightarrow{OH^{-}} A$ $\xrightarrow{\Delta} B$; the product $B$ is