Reactions of Alkyl Halides

Q. The compound which undergoes $S_{N}1$ reaction most rapidly is:

1. 
2. 
3. 
4. 

Q.

Name a gas which gives a black ppt when passed through copper sulphate solution.

Q. Which of the following compound will undergo $S_{N}1$ reaction?

1. 
2. All the above
3. 
4. 

Q. An optically active compound A upon acid catalysed hydrolysis yields two optically active compounds B and C by pseudo first order kinetics with respect to A. The observed rotation of the mixture after 20 min was 5° while after completion of the reaction it was – 20°. If optical rotation per molar concentration of A, B and C are 60°, 40° and – 80° respectively and observed rotation of a compound is directly proportional to concentration of that compound. (Take optical rotation in degree)

$\begin{array}{cc}\text{List -I}& \text{List -II}\\ \text{(I) Rate constant of the reaction (in}hou{r}^{-1})& \left(P\right)1.0\\ \text{(II) Initial concentration of compound A (in M)}& \left(Q\right)2.08\\ \text{(III) If the initial concentratrion of A is 0.8 M then}& \left(R\right)0.5\\ \text{the observed optical rotation of mixture after 1 hour}& \\ \text{(IV) If initially along with A;B and C are also present with}& \left(S\right)-22\\ \text{initial concentration [A] = 0.4M, [B] = 0.1 M and [C] = 0.2 M}& \\ \text{then net observed optical rotation of the mixture after 40 min.}& \left(T\right)22\\ & \left(U\right)-18\end{array}$

Which of the following options has the correct combination considering List-I and List-II

1. (III), (U)
2. (IV), (U)
3. (III), (S)
4. (IV), (S)

Q. During the course of a $S_{N}1$ reaction, the intermediate species formed is:

1. a carbocation
2. a free radical
3. an intermediate complex
4. a carbanion

Q. The decreasing order of relative nucleophilicity of the following nucleophiles in a protic solvent is
$S{H}^{-},Ac{O}^{-},Ph{O}^{-},O{H}^{-},H_{2}O$

1. $S{H}^{-}>O{H}^{-}>H_{2}O>Ac{O}^{-}>Ph{O}^{-}$
2. $S{H}^{-}>O{H}^{-}>Ph{O}^{-}>Ac{O}^{-}>H_{2}O$
3. $S{H}^{-}>Ph{O}^{-}>O{H}^{-}>H_{2}O>Ac{O}^{-}$
4. $O{H}^{-}>S{H}^{-}>Ph{O}^{-}>Ac{O}^{-}>H_{2}O$

Q. In a Nucleophilic substitution unimolecular $\left(S_{N}1\right)$ reaction:

1. Formation of carbocation intermediate takes place.
2. Formation of carbanion intermediate takes place.
3. None of the above.
4. Formation of free radical intermediate takes place.

Q. The order of decreasing nucleophilicity is

1. $H_{2}O>O{H}^{-}>C{H}_{3}CO{O}^{-}>C{H}_3{O}^{-}$
2. $C{H}_{3}CO{O}^{-}>C{H}_3{O}^{-}>H{O}^{-}>H_{2}O$
3. $H{O}^{-}>C{H}_3{O}^{-}>C{H}_{3}CO{O}^{-}>H_{2}O$
4. $C{H}_3{O}^{-}>O{H}^{-}>C{H}_{3}CO{O}^{-}>H_{2}O$