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

(N/A) $(i)$ $\text{Cyanohydrin}$: Formed by the addition of $HCN$ to aldehydes or ketones. Example: $CH_3CHO + HCN \rightarrow CH_3CH(OH)CN$ (Acetaldehyde cyanohydrin).
$(ii)$ $\text{Acetal}$: Formed when an aldehyde reacts with two equivalents of a monohydric alcohol in the presence of dry $HCl$. Example: $CH_3CHO + 2C_2H_5OH \xrightarrow{dry \ HCl} CH_3CH(OC_2H_5)_2 + H_2O$.
$(iii)$ $\text{Semicarbazone}$: Formed by the reaction of an aldehyde or ketone with semicarbazide. Example: $CH_3CHO + NH_2NHCONH_2 \rightarrow CH_3CH=NNHCONH_2 + H_2O$.
$(iv)$ $\text{Aldol}$: $A$ $\beta$-hydroxy aldehyde or ketone formed by the condensation of two molecules of an aldehyde or ketone containing $\alpha$-hydrogen. Example: $2CH_3CHO \xrightarrow{dil. NaOH} CH_3CH(OH)CH_2CHO$.
$(v)$ $\text{Hemiacetal}$: Formed by the addition of one molecule of alcohol to an aldehyde. Example: $CH_3CHO + C_2H_5OH \xrightarrow{HCl} CH_3CH(OH)(OC_2H_5)$.
$(vi)$ $\text{Oxime}$: Formed by the reaction of aldehydes or ketones with hydroxylamine $(NH_2OH)$. Example: $CH_3CHO + NH_2OH \rightarrow CH_3CH=NOH + H_2O$.
$(vii)$ $\text{Ketal}$: Formed by the reaction of a ketone with two equivalents of alcohol or a diol. Example: $CH_3COCH_3 + HOCH_2CH_2OH \xrightarrow{HCl} \text{Ethylene glycol ketal}$.
$(viii)$ $\text{Imine}$: Compounds containing a carbon-nitrogen double bond $(>C=NH)$,formed by reaction with ammonia. Example: $CH_3CHO + NH_3 \rightarrow CH_3CH=NH + H_2O$.
$(ix)$ $2,4-DNP$ $\text{derivative}$: Formed by the reaction of carbonyl compounds with $2,4$-dinitrophenylhydrazine. Example: $R_2C=O + H_2NNHC_6H_3(NO_2)_2 \rightarrow R_2C=NNHC_6H_3(NO_2)_2 + H_2O$.
$(x)$ $\text{Schiff's base}$: An imine formed by the reaction of an aldehyde or ketone with a primary amine $(RNH_2)$. Example: $CH_3CHO + CH_3NH_2 \rightarrow CH_3CH=NCH_3 + H_2O$.