Electrophiles and Nucleophiles

Q.

Out of aldehydes and ketones which one is more reactive and why?

Q. Which of the following is least reactive towards a nucleophilic attack?

1. Acetaldehyde
   
2. Ditert-Butyl ketone
3. Butanone
4. Diisopropyl ketone

Q.

Why is allyl compound more reactive towards nucleophilic substitution than alkyl compounds?

Q. Which of the following is more reactive towards nucleophilic addition reaction?

1. $$C{H}_{3}COC{H}_3$$
2. $$HCHO$$
3. $$C{H}_{3}CHO$$
4. $$C{H}_{3}C{H}_{2}CHO$$

Q. In an octahedral structure, the pair of d-orbitals involved in $d^{2}s{p}^3$ hybridisation is :

1. $d_{x^2-y^2},d_{z^2}$
2. $dxz,d_{x^2-y^2}$
3. $d_{z^2},d_{xz}$
4. $d_{xy},d_{yz}$

Q.

What are Sn ar and e1 cb reactions and how to identify or differentiate them from other mechanisms(Sn 1, Sn 2, E1, E2)?

Q. Which one of the following cyano complexes would exhibit the lowest value of paramagnetic behavior?

1. $\left[Co\right(CN{)}_6{]}^{3-}$
2. $\left[Fe\right(CN{)}_6{]}^{3-}$
3. $\left[Mn\right(CN{)}_6{]}^{3-}$
4. $\left[Cr\right(CN{)}_6{]}^{3-}$

Q. The orbitals involved in case of $s{p}^3{d}^2$ hybridisation is

1. $s+p_x+p_y+d_{xy}+p_z+d_{z^2}$
2. $s+p_x+p_y+d_{z^2}+p_z+d_{yz}$
3. $s+p_x+p_y+p_z+d_{z^2}+d_{x^2-y^2}$
4. $s+p_x+p_y+p_z+d_{yz}+d_{xz}$

Q. Least reactive towards nucleophilic addition among the following is

1. $HCHO$
2. 
3. 
4. $C{H}_{3}CHO$

Q. $B{F}_3$ is planar and electron deficient compound. Hybridisation and number of electrons around the central atom, respectively are:

1. $s{p}^3\text{and}4$
2. $s{p}^3\text{and}6$
3. $s{p}^2\text{and}6$
4. $s{p}^2\text{and}8$

Q. Explain why this reaction takes place in anti markownikoff regiochemistry. ?
CF3CH=CH2+HCL give rise to CH3CH2CH2CL

Q. The product of the following reactions is (are):
$C_2{H}_{5}Br+2Na+C{H}_{3}Br\stackrel{\text{dry ether}}{\to }$?

1. ethane
2. propane
3. butane
4. ethane, propane and butane

Q. Give the decreasing order of nucleophilic addition reaction of the followings:
(i) $HCHO$
(ii) $PhCHO$
(iii) Chloral $(C{l}_{3}C-CH=O)$
(iv) Acetophenone

1. (iii) > (i) > (ii) > (iv)
2. (iv) > (ii) > (i) > (iii)
3. (i) > (iii) > (ii) > (iv)
4. (iii) > (i) > (iv) > (ii)

Q.

Is a Carbanion Nucleophile?

Q. The hybridisation of boron in $B{H}_3$ molecule is .

1. $s{p}^3$
2. $s{p}^2$
3. $sp$
4. $s{p}^{3}d$

Q. A compound of molecular formula $C_8{H}_8{O}_2$ reacts with acetophenone to form a single cross-aldol product in the presence of base. The same compound on reaction with conc. NaOH forms benzyl alcohol as one of the products. The structure of the compound is :

1. 
2. 
3. 
4. 

Q. Increasing order of reactivity of $C{H}_{3}CHO,C{H}_{3}CO{C}_2{H}_5\text{and}C{H}_{3}COC{H}_3$ towards nucleophilic addition is:

1. $C{H}_{3}CHO>C{H}_{3}COC{H}_3>C{H}_{3}CO{C}_2{H}_5$
2. $C_2{H}_{5}COC{H}_3>C{H}_{3}COC{H}_3>C{H}_{3}CHO$
3. $C{H}_{3}COC{H}_3>C{H}_{3}CHO>C_2{H}_{5}COC{H}_3$
4. $C{H}_{3}COC{H}_3>C_{2}H5COC{H}_3>C{H}_{3}CHO$

Q. Which of the following cannot exhibit $s{p}^{3}d$ hybridization?
(a) $C$
(b) $P$
(c) $Cl$
(d) $B$

1. a, c
2. a, d
3. b, c
4. b, d

Q. Acetaldehyde and benzaldehyde can be differentiated by :

1. Tollen's reagent
2. Iodoform test
3. Fehling test
4. both (a) and (b)

Q.
In the above reactions product \(A\) and product \(B\) respectively are
\( NH _{2} \stackrel{ KOBr }{\longrightarrow} \) (major product) \( NH _{2} \stackrel{ LiAlH _{4}}{ H _{2} O ^{+}} \underset{\text { (major product) }}{ B } \)

Q. Can a -NO2 group be converted to -NH2 with the help of lithiumaluminiumhydride?

Q. The hybridisation of boron in $B{H}_3$ molecule is .

1. $s{p}^3$
2. $s{p}^2$
3. $sp$
4. $s{p}^{3}d$

Q.
Which of the following statement(s) is/are correct about the given reaction?

1. The compounds (B) and (C), respectively, are $Et-CN$ and $EtN{H}_2$
2. The compounds (B) and (C), respectively, are $EtN=C=O$ and $EtNHCOOEt$
3. The reaction is known as Lossen rearrangement reaction
4. The reaction proceeds via the formation of acyl carbene as the intermediate species

Q. Which of the following reaction(s) is/are correct?
(Only organic products are given)

1. $H_{3}COC{H}_{2}C{H}_3+PC{l}_5\to H_{3}CCl+EtCl$
2. $H_{3}C-\stackrel{O}{\stackrel{||}{C}}-OH+PC{l}_5\to H_{3}C-\stackrel{O}{\stackrel{||}{C}}-Cl$
3. $H_{3}C-\stackrel{O}{\stackrel{||}{C}}-C{H}_3+PC{l}_5\to H_{3}C-\stackrel{Cl}{\stackrel{|}{C}}H-Cl$
4. $\text{Cyclohexanol}+PC{l}_5\to \text{Chlorocyclohexane}$

Q. What will be the oder of reactivity of the following carbonyl compound with Grignard's reagent?

1. $$I>II>III>IV$$
2. $$IV>III>II>I$$
3. $$II>I>IV>III$$
4. $$III>II>I>IV$$

Q. An organic compound $A\left(C_3{H}_{7}Cl\right)$ on reaction with Na/diethyl ether gives a hydrocarbon which on monochlorination gives only two chloro derivative, then A is

1. tertiary butyl chloride
2. isobutyl chloride
3. secondary butyl chloride
4. isopropyl chloride

Q. $\begin{array}{cc}\text{Column - I}& \text{Column - II}\\ \text{(i)}{S}_{N}1\text{reaction}& \text{(A)}vic\text{-dihalide}\\ \text{(ii) Alkylidene halides}& \text{(B)}gem\text{-dihalide}\\ \text{(iii) Bromination}& \text{(C) Racemisation}\\ \text{(iv) Elimination of}HX& \text{(D) Saytzeff rule}\end{array}$
Which of the following is the best matched option?

1. i-C, ii- D, iii- A, iv-B
2. i-C, ii- B, iii- A, iv-D
3. i-D, ii- B, iii- A, iv-C
4. i-D, ii- A, iii- B, iv-C

Q. Which of the following statements is not correct for a nucleophile ?

1. Nucleophiles attack low $e^{-}$ density sites
2. Nucleophile is a Lewis acid
3. Nucleophiles are not electron seeking
4. Ammonia is a nucleophile

Q. Which of the following is the least reactive towards a nucleophile?

1. Methanal
2. 2-Pentanone
3. Propanal
4. 3-Pentanone

Q. Which does not gives iodoform test:-

1. $Ph-\stackrel{\stackrel{OH}{|}}{C}H-C{H}_3$
2. $Ph-\underset{\underset{O}{||}}{C}-C{H}_3$
3. $I-C{H}_2-\underset{\underset{O}{||}}{C}-H$
4. $C{H}_3-C{H}_2-\underset{\underset{O}{||}}{C}-O-C{H}_3$