KCET PYQs for Haloalkanes and Haloarenes with Solutions: Practice KCET Previous Year Questions

1.

A haloalkane undergoes $S_{N^2}$ or $S_{N^1}$ reaction depending on:

• Solvent used in the reaction
• Low temperature
• The type of halogen atom
• Stability of the haloalkane

2.

In the following scheme of reaction.

X, Y and Z respectively are:

• AgF, alcoholic KOH, benzene
• HF, aqueous KOH, Na in dry ether
• $Hg_2F_2$​, alcoholic KOH, Na in dry ether
• $CoF_2$​, aqueous KOH, benzene

3.

Ethyl chloride on heating with $AgCN$, forms a compound $'X'$ . The functional isomer of $'X'$ is -

• $C_2H_5NC$
• $C_2H_5NH_2$
• $C_2 H_5 CN$
• None of the these

4.

An organic compound on heating with $CuO$ produces $CO_2$, but no water. The organic compound may be

• Methane
• Ethyl iodide
• Carbon tetrachloride
• Chloroform

5.

An organic compound which produces a bluish green coloured flame on heating in presence of copper is

• chlorobenzene
• benzaldehyde
• aniline
• benzoic acid

6.

2-Methyl propane can be prepared by Wurtz reaction. The haloalkanes taken along with metallic sodium and dry ether are:

• chloromethane and 2-chloropropane
• chloroethane and chloromethane
• chloroethane and 1-chloropropane
• chloromethane and 1-chloropropane

7.

Which of the following pairs are correctly matched? Reactants Products I. $Rx+AgOH (aq)$ RH II. $Rx+AgCN_{(alc)}$ RNC III. $Rx+KCN_{(alc)}$ RNC IV. $Rx+Na_{\text{(ether)}}$ R-R

• Only I
• $I$ and $II$
• $II$ and $III$
• $II$ and $IV$

8.

2-Methylpropane can be prepared by Wurtz reaction. The haloalkanes taken along with metallic sodium and dry ether are:

• Chloromethane and 2-chloropropane
• Chloroethane and chloromethane
• Chloroethane and 1-chloropropane
• Chloromethane and 1-chloropropane

9.

In the given sequence of reactions, identify ‘P’, ‘Q’ and ‘S’ respectively:

• Br₂, Alc, KOH, NaOH, Al₂O₃
• HBr, Alc, KOH, CaC₂, KMnO₄
• HBr, Alc, KOH, NaNH₂, Red hot iron tube
• Br₂, Alc, KOH, NaNH₂, Red hot iron tube

10.

Which of the following is not true for $S_N1$ reaction ?

• Favoured by polar solvents
• $3^\circ$ - alkyl halides generally react through $S_N1$ reaction
• The rate of the reaction does not depend upon the molar concentration of the nucleophile
• $1^\circ$ - alkyl halides generally react through $S_N1$ reaction.

11.

Following is the substitution reaction in which \(-CN\) replaces \(-Cl\)
\(R - CI + KCN \overset{\Delta}{\rightarrow} R - CN + KCI\)
To obtain propane nitrile, \(R-Cl\) should be:

• chloroethane
• $1$-chloropropane
• chloromethane
• $2$-chloropropane

12.

But-1-yne on reaction with dilute H2​SO4​ in the presence of Hg2+ ions at 333K gives:

13.

How many chiral carbon atoms are present in $2,3,4$ - trichloropentane ?

• 3
• 2
• 1
• 4