In thin layer chromatography,a substance moved by a distance of $4 \ cm$,whereas the solvent moved by a distance of $5 \ cm$. Then the value of retardation factor $(R_f)$ is

When the $TLC$ solvent reaches a height of $10 \, cm$,compound $(A)$ reaches $8 \, cm$ and compound $(B)$ reaches $6 \, cm$. Calculate the $R_f$ values of $(A)$ and $(B)$.

Identify the correct statements from the following:
$(i)$ Electromeric effect is a permanent effect.
$(ii)$ Hyperconjugation is a temporary effect.
$(iii)$ Fractional distillation is used to separate two liquids from a mixture if the difference in their boiling points is less.
$(iv)$ Different compounds are adsorbed on an adsorbent to different extents.

Consider the following table$-$

Column-$I$	Column-$II$
$(A).$ Best and latest technique for isolation,purification and separation of organic compounds	$(i).$ Chromatography
$(B).$ In Lassaigne's test for $N$	$(ii).$ Vacuum distillation (distillation under reduced pressure)
$(C).$ In Lassaigne's test for $S$	$(iii).$ Violet coloured complex is formed
$(D).$ Aniline is purified from water by	$(iv).$ Prussian blue coloured complex is formed
$(E).$ Glycerol is purified from spent lye	$(v).$ Steam distillation

The correct match is $-$

The correct match between Item $I$ and Item $II$ is

Item $I$	Item $II$
$a$. Benzaldehyde	$p$. Mobile phase
$b$. Alumina	$q$. Adsorbent
$c$. Acetonitrile	$r$. Adsorbate

What is a theoretical plate?