In a S_N2 substitution reaction of the type 
 $\mathrm{R}-\mathrm{Br}+{\mathrm{Cl}}^{-}\stackrel{\mathrm{DMF}}{\to }\mathrm{R}-\mathrm{Cl}+{\mathrm{Br}}^{-}$
which one of the following has the highest relative rate?

1.  ${\mathrm{CH}}_3-{\mathrm{CH}}_2-{\mathrm{CH}}_2\mathrm{Br}$

2.  ${\mathrm{CH}}_3-\underset{\mathrm{Br}}{\underset{|}{\mathrm{CH}}}-{\mathrm{CH}}_2\mathrm{Br}$

3.  ${\mathrm{CH}}_3-\underset{{\mathrm{CH}}_3}{\overset{{\mathrm{CH}}_3}{\underset{\left|}{\overset{\right|}{\mathrm{C}}}}}-{\mathrm{CH}}_2\mathrm{Br}$

4.  ${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{Br}$

Which one is most reactive towards S_N1 reaction?

1. $C_6{H}_{5}CH\left(C_6{H}_5\right)Br$

2. $C_6{H}_{5}CH\left(C{H}_3\right)Br$

3. $C_6{H}_{5}C\left(C{H}_3\right)\left(C_6{H}_5\right)Br$

4. $C_6{H}_{5}C{H}_{2}Br$

In the following sequence of reactions, 
${\mathrm{CH}}_3-\mathrm{Br}\stackrel{\mathrm{KCN}}{\to }\mathrm{A}\stackrel{{\mathrm{H}}_3{\mathrm{O}}^{+}}{\to }\mathrm{B}\underset{\mathrm{ether}}{\overset{{\mathrm{LiAlH}}_4}{\to }}\mathrm{C}$ 
The end product (C) is

1. Acetone

2. Methane

3. Acetaldehyde

4. Ethyl alcohol

Which of the following compounds will undergo racemisation when solution of KOH hydrolysis? 
(i)  (ii) CH₃CH₂CH₂Cl (iii) ${\mathrm{H}}_3\mathrm{C}-\stackrel{{\mathrm{CH}}_3}{\stackrel{|}{\mathrm{CH}}}-{\mathrm{CH}}_2\mathrm{Cl}$ (iv) 

1. (i) and (ii)

2. (ii) and (iv)

3. (iv) only

4. (i) and (iv)

The compound A on treatment with Na gives B, and with PCl₅ gives C. B and C react together to give diethyl ether. A, B and C are in the order of: 

1. ${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}, {\mathrm{C}}_2{\mathrm{H}}_6, {\mathrm{C}}_2{\mathrm{H}}_5\mathrm{Cl}$

2. ${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}, {\mathrm{C}}_2{\mathrm{H}}_5\mathrm{Cl}, {\mathrm{C}}_2{\mathrm{H}}_5\mathrm{ONa}$

3. ${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{Cl}, {\mathrm{C}}_2{\mathrm{H}}_6, {\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}$

4. ${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}, {\mathrm{C}}_2{\mathrm{H}}_5\mathrm{ONa} ,{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{Cl}$

Consider the reaction 
CH₃ CH₂ CH₂ Br + NaCN - CH₃ CH₂ CH₂ CN + NaBr 
This reaction will be the fastest in

1.  Ethanol

2.  Methanol

3.  N, N'-dimethylformamide (DMF)

4.  water

Which of the following is the halogen exchange reaction?

1.	R X + NaI \(\xrightarrow{\text{ Acetone }}\) RI + NaX
2.
3.	R - OH + HX \(\xrightarrow{\text{ ZnCl}_2~~}\) R - X + H2O
4.