List of top Chemistry Questions on Haloalkanes And Haloarenes

Answer the following: (I) Which isomer of C$_4$H$_9$Br is most reactive towards S$_N$1 reaction? (II) Predict the alkene that would be formed by dehydrohalogenation of 1-Bromo-1-methylcyclohexane. (III) Although chlorine shows strong $-I$ effect, yet it is ortho/para-directing in electrophilic aromatic substitution reactions. Why? (ii) Write the major product in the following reactions: (I)

(II)

(I) Which of the following is more reactive towards S$_N$1 reaction: 2-Bromo-2-methylbutane or 1-Bromopentane (II) What type of halide is present in the following compound: \[ \begin{array}{c} CH_3-CH-C=CH_2\\ |\\ CH_3 \end{array} \] \[ | \] \[ Cl \] (III) Why is chloroform stored in dark coloured bottles? (ii) Define the following terms: (I) Ambident Nucleophiles (II) Racemic mixture

Consider the following reaction and identify A and B : \[ CH_3Cl + NaI \xrightarrow[\text{dry acetone}]{} A + B \]

Give reasons for the following : (a) Alkyl halides, though polar, yet their solubility in water is very low.

Give reasons for the following : (b) p-Dichlorobenzene has higher melting point than those of o- and m-isomers.

For the compound having molecular formula C$_4$H$_9$Br, write : (a) the isomer which is most reactive towards SN1 displacement. (b) the isomer which, on reacting with Na metal in the presence of dry ether, gives 2,5-Dimethylhexane.

Give reasons for the following: \[ (a)\;\text{Although chlorine is an electron-withdrawing group, yet it is ortho-, para-directing in electrophilic aromatic substitution reactions.} \] \[ (b)\;\text{Aryl halides cannot be prepared by reacting phenol with concentrated halogen acids or phosphorus halides.} \] \[ (c)\;\text{Chloroform is stored in closed dark coloured bottles.} \]

For the compound having molecular formula \(C_4H_9Br\), write:
(a) the isomer which is most reactive towards S_N1 displacement.
(b) the isomer which, on reacting with Na metal in dry ether, gives 2,5-dimethylhexane.

Arrange the compounds in order of their increasing boiling points. (A) 1-bromoethane (B) 1-bromobutane (C) 2-bromo-2-methylpropane (D) 2-bromobutane

Compound 'X' with molecular formula \(C_4H_9Br\) reacts with aqueous KOH to give an alcohol. The rate of this reaction depends only on the concentration of the compound 'X'. When an optically active isomer 'Y' of the compound 'X' was treated with aqueous KOH solution, the rate of reaction was found to be dependent on concentration of compound 'Y' and aqueous KOH both.

(a) Write down the structural formula of both 'X' and 'Y'.

(b) Out of 'X' and 'Y', which one will undergo racemisation and why?

(c) Out of 'X' and 'Y', which one will form product with inversion of configuration and why?

Why are haloarenes less reactive towards nucleophilic substitution reaction? Give two reasons.

Which of the following is 'not' true about enantiomers?

Give reasons for the following :
(a) Haloalkanes react with KCN to form alkyl cyanides, while with AgCN they form isocyanides.
(b)

is more reactive towards $\mathrm{S_N2}$ displacement as compared to

.
(c) Grignard reagents should be prepared under anhydrous conditions.

For the compound having molecular formula $\mathrm{C_4H_9Br}$, write :
(a) the isomer which is most reactive towards $\mathrm{S_N1}$ displacement.
(b) the isomer which, on reacting with Na metal in the presence of dry ether, gives 2,5-Dimethylhexane.

Consider the following compounds : Chlorobenzene (I), 2,4,6-trinitrochlorobenzene (II), 2,4-dinitrochlorobenzene (III), 4-nitrochlorobenzene (IV).
The correct order of increasing rate of nucleophilic substitution reactions of these compounds is :

Consider the following compounds : Chlorobenzene (I), 2,4,6-trinitrochlorobenzene (II), 2,4-dinitrochlorobenzene (III), 4-nitrochlorobenzene (IV). The correct order of increasing ease of nucleophilic substitution reactions of these compounds is :

Compound ‘X’ with molecular formula \( C_4H_9Br \) reacts with aqueous KOH to give an alcohol. The rate of this reaction depends only on the concentration of compound ‘X’. When an optically active isomer ‘Y’ of the compound ‘X’ was treated with aqueous KOH solution, the rate of reaction was found to be dependent on concentration of compound ‘Y’ and aqueous KOH both.

22(a). Write down the structural formula of both ‘X’ and ‘Y’.

Consider the following reaction and identify A and B: \[ CH_3Cl + NaI \xrightarrow{\text{dry acetone}} A + B \]

Which of the following is least reactive towards nucleophilic substitution (\( S_N1 \))?

Identify the products X and Y formed in the following reactions:

(i) CH3CH2OH + PCl5 → X + POCl3 + HCl

(ii) CH3Br + AgF → Y + AgBr

Out of ‘X’ and ‘Y’ , which one will form product with inversion of configuration and why?

Out of ‘X’ and ‘Y’, which one will undergo racemisation and why?

Why are haloarenes less reactive towards nucleophilic substitution reaction? Give two reasons.