At which value of $n$ does the formation of a six-membered ring take place in the following reaction?
$Br-(CH_2)_n-CH_2-Br + CH_2(CO_2Et)_2 \xrightarrow{NaOEt, EtOH} \text{cyclic product}$

Give simple chemical tests to distinguish between the following pairs of compounds.
$(i)$ Propanal and Propanone
$(ii)$ Acetophenone and Benzophenone
$(iii)$ Phenol and Benzoic acid
$(iv)$ Benzoic acid and Ethyl benzoate
$(v)$ Pentan$-2-$one and Pentan$-3-$one
$(vi)$ Benzaldehyde and Acetophenone
$(vii)$ Ethanal and Propanal

How will you bring about the following conversions in not more than two steps?
$(i)$ Propanone to Propene
$(ii)$ Benzoic acid to Benzaldehyde
$(iii)$ Ethanol to $3-$Hydroxybutanal
$(iv)$ Benzene to $m-$Nitroacetophenone
$(v)$ Benzaldehyde to Benzophenone
$(vi)$ Bromobenzene to $1-$Phenylethanol
$(vii)$ Benzaldehyde to $3-$Phenylpropan$-1-$ol
$(viii)$ Benzaldehyde to $\alpha-$Hydroxyphenylacetic acid
$(ix)$ Benzoic acid to $m-$Nitrobenzyl alcohol

$C_6H_6$ $\xrightarrow[AlCl_3]{(CH_3)_2CHCOCl}$ $\xrightarrow[\text{reduction}]{\text{Clemmensen}}$ $\xrightarrow[AlCl_3]{CH_3COCl}$ $\xrightarrow[\text{Red } P + HI]{H_3O^{\oplus}} (\text{Ibuprofen})$
Ibuprofen is

Choose the response that matches the correct functional group classification with the following group of structural formulas.

Match List-$I$ with List-$II$:

List-$I$ (Test)	List-$II$ (Identification)
$A$. Bayer's test	$I$. Phenol
$B$. Ceric ammonium nitrate test	$II$. Aldehyde
$C$. Phthalein dye test	$III$. Alcoholic-$OH$ group
$D$. Schiff's test	$IV$. Unsaturation

Choose the correct answer from the options given below: