Chemistry MCQs for NEET — Practice Questions with Answers

(d) $\mathrm{RCHO}$ or $\mathrm{RCOR}$ can be reduced to ${\mathrm{RCH}}_2\mathrm{OH}$ or $\mathrm{RCHOHR}$ respectively by ${\mathrm{H}}_2$ + catalyst, ${\mathrm{LiAlH}}_4, {\mathrm{NaBH}}_4,$ etc.

Schiff's reagent is a magenta solution decolorized with sulfurous acid (SO2). It is used for the detection of aldehydes in organic compounds. When Schiff's reagent is added to an aldehyde-containing compound, it forms a colored compound, indicating the presence of the aldehyde group.

(c) Rest all are polymerization.

The molecular formula C3H6O can represent various compounds, including cyclic ether (e.g., oxirane), carbonyl compounds (e.g., acetone), unsaturated ethers (e.g., vinyl methyl ether), and unsaturated alcohols (e.g., propargyl alcohol). Therefore, the correct option is 'all of the above'.

(b) $3\left({\mathrm{CH}}_3\mathrm{CHO}\right)\underset{\mathrm{Dil}. {\mathrm{H}}_2{\mathrm{SO}}_4}{\overset{\mathrm{Conc}. {\mathrm{H}}_2{\mathrm{SO}}_4}{\rightleftharpoons }}({\mathrm{CH}}_3\mathrm{CHO}{)}_3$

(a) $(C{H}_3{)}_2$CHCHO shows both reactions, i.e., aldol condensation and Cannizzaro's reaction

(c) CH₃CHO$\stackrel{{\mathrm{PCl}}_5}{\to }$CH₃CHl₂

(b) R$—$CN$\stackrel{{\mathrm{SnCl}}_2+\mathrm{HCl}}{\to }$RCHO+NH₄Cl+SnCl₄

(c) Ketones shows condensation only.

(b) Tischenko's reaction is a modified Cannizzaro's reaction given by all aldehydes, 2RCHO$\underset{∆}{\overset{\mathrm{Al}({\mathrm{OC}}_2{\mathrm{H}}_5{)}_3}{\to }}$ RCOOH+RCH₂OH$\to$RCOOH₂R