Chapter 26

In which of the following cases rate is independent upon concentration of nucleophile?

Which of the following will not form a Grignard reagent on treatment with \(\mathrm{Mg}\) in dry ether? (a) \(\mathrm{BrCH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Br}\) (b) \(\mathrm{Br} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Br}\) (c) \(\mathrm{BrCH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Br}\) (d) All the three above can form Grignard reagent.

Ethyl bromide can be convert into ethyl alcohol by: (a) Heating with aqueous KOH. (b) Heating with alc \(\mathrm{KOH}\) (c) Heating with dry silver oxide (d) Heating with moist silver oxide.

Identify the reaction in which Hofmann product could be the major product? (a) 2 - chlorohexane \(\frac{\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{O}^{-}}{\mathrm{C}_{2} \mathrm{H}_{3} \mathrm{OH}}\) (b) 2 - fluorohexane \(\frac{\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{O}^{-}}{\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}}\) (c) 2- iodohexane \(\frac{\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{O}^{-}}{\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}}\) (d) 2 - bromohexane \(\frac{\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{O}^{-}}{\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}}\)

Consider the following statements for Friedel Craft's reaction. Which of the following statement is incorrect? (a) The entering alkyl group is an activating group; hence polyalkylation is possible. (b) Rearrangement in alkylating group is possible when the Lewis acid used is \(\mathrm{AlCl}_{3}\). (c) Aryl halides are more effect than alkyl halide as halide component. (d) Aromatic compounds containing \(\mathrm{m}\)-directing group cannot give this reaction

Match the following: List I (Reactants) 1\. \(\mathrm{CH}_{3}\left(\mathrm{CH}_{2}\right)_{3} \mathrm{OH} \stackrel{\mathrm{NaBr}, \mathrm{H}_{2} \mathrm{SO}_{4}, \Delta}{\longrightarrow}\) 2\. \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{COH} \frac{\text { Conc. } \mathrm{HCl}}{\text { Roser temp }}\) 3\. \(\mathrm{CH}_{3} \mathrm{CH}(\mathrm{OH})\left(\mathrm{CH}_{2}\right)_{2} \mathrm{CH}_{3} \stackrel{\mathrm{PB}_{3}}{\longrightarrow}\) 4\. \(\mathrm{Me}_{2} \mathrm{CHCH}_{2} \mathrm{OH} \stackrel{\mathrm{soc} \mathrm{h}}{\longrightarrow}\) List II (Alkyl halides) A. \(\mathrm{CH}_{3} \mathrm{CHBr}\left(\mathrm{CH}_{2}\right)_{2} \mathrm{CH}_{3}\) B. \(\mathrm{Me}_{2} \mathrm{CHCH}_{2} \mathrm{Cl}\) C. \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CCl}\) D. \(\mathrm{CH}_{3}\left(\mathrm{CH}_{2}\right)_{3} \mathrm{Br}\) The correct matching is \(\begin{array}{lllll} & 1 & 2 & 3 & 4 \\ \text { (a) } \mathrm{C} & \mathrm{D} & \mathrm{B} & \mathrm{A}\end{array}\) (b) \(\mathrm{C}\) \(\mathrm{D} \quad \mathrm{A} \quad \mathrm{B}\) (c) D \(\mathrm{C} \quad \mathrm{A} \quad \mathrm{B}\) (d) D C \(\mathrm{A}\)

Match the following: List I (Reactants) 1\. \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Br}+\) alc. \(\mathrm{KOH}\) 2\. \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}(\mathrm{Br}) \mathrm{CH}_{3}+\) alc. \(\mathrm{KOH}\) 3\. \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CBr}+\) alc. \(\mathrm{KOH}\) List II (Products) A. cis-but-2-ene B. trans-but-2-ene C. but-1-ene D. 2 -methylprop-l-ene The correct matching is \(\begin{array}{lll}1 & 2 & 3\end{array}\) 123 (a) \(\mathrm{C} \mathrm{B} \mathrm{D}\) (b) \(\mathrm{C} \mathrm{A} \mathrm{D}\) (c) \(\mathrm{C} \mathrm{D} \mathrm{A}\) (d) \(\mathrm{B} \mathrm{A} \mathrm{C}\)

Match the following (a) \(\mathrm{RI}>\mathrm{RBr}>\mathrm{RCl}\) (p) Order of reactivity \(>\) RF \(\quad\) towards \(S_{N^{2}}\) process (b) \(\mathrm{RF}>\mathrm{RCl}>\mathrm{RBr}\) (q) Decreasing order \(>\) RI \(\quad\) of B.pt. (c) \(3^{\circ}>2^{\circ}>1^{\circ}\) (r) Decreasing order of (hydrocarbon) density (d) \(1^{\circ}>2^{\circ}>3^{\circ}\) (s) stability order (alkyl halide) (t) Order of replacement of \(\mathrm{H}\) atom

Match the following (a) Acetylsalicylic acid (p) Insecticide (b) DDT (q) Drug (c) Naphthalene (r) Moth repellent (d) Carbon tetrahcloride (s) Fire extinguisher (t) Sublimation

Number of isomers (aromatic) possible with molecular formula \(\mathrm{C}_{\mathrm{g}} \mathrm{H}_{9} \mathrm{Cl}\) which do not contain \(\mathrm{Cl}\) atom in aromatic nucleus is

1, 2 dibromopropane on treatment with \(X\) moles of \(\mathrm{NaNH}_{2}\) followed by treatment with ethyl bromide gave a pentyne, the value of \(\mathrm{X}\) is

\(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CBr} \stackrel{\left(\mathrm{CH}_{3}\right)_{3} \mathrm{C} \overline{\mathrm{O}} \mathrm{K}^{+}}{\longrightarrow}(\mathrm{A}) \stackrel{\mathrm{NBS}}{\longrightarrow}\) (B) \(\frac{\text { Cold alk. }}{\mathrm{KMnO}_{4}}\) (C). The total number of stereisomers possible for the compound (C) are?

\(\mathrm{CH}_{3} \mathrm{MgI}\) is an organometallic compound due to (a) \(\mathrm{Mg}-\mathrm{I}\) bond (b) C-I bond (c) \(\mathrm{C}-\mathrm{Mg}\) bond (d) C-H bond

Bottles containing \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{I}\) and \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}_{2} \mathrm{I}\) lost their orig- inal labels. They were labelled \(\mathrm{A}\) and \(\mathrm{B}\) for testing. A and B were separately taken in test tubes and boiled with \(\mathrm{NaOH}\) solution. The end solution in each tube was made acidic with dilute \(\mathrm{HNO}_{3}\) and some \(\mathrm{AgNO}_{3}\) solution added. Solution B gave a yellow precipitate. Which one of the following statements is true for the experiment? [2003] (a) \(\mathrm{A}\) is \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}_{2} \mathrm{I}\) (b) \(\mathrm{A}\) is \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{I}\) (c) B is \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{I}\) (d) addition of \(\mathrm{HNO}_{3}\) was unnecessary

The compound formed on heating chlorobenzene with chloral in the presence of concentrated sulphuric acid is [2004] (a) gammexane (b) DDT (c) freon (d) hexachloroethane

Acetyl bromide reacts with excess of \(\mathrm{CH}_{3} \mathrm{MgI}\) followed by treatment with a saturated solution of \(\mathrm{NH}_{4} \mathrm{Cl}\) gives \([2004]\) (a) acetone (b) acetamide (c) 2 -methyl-2-propanol (d) acetyl iodide

Which of the following will have a mesoisomer also? \(\quad[2004]\) (a) 2,3 -dichlorobutane (b) 2,3 -dichloropentane (c) 2 -hydroxypropanoic acid (d) 2 -chlorobutane

Which of the following compounds is not chiral? [2004] (a) 2-chloropentane (b) 1 -chloropentane (c) 3 -chloro-2-methylpentane (d) 1 -chloro-2-methylpentane

Alkyl halides react with dialkyl copper reagents to give \([\mathbf{2 0 0 5}]\) (a) alkenes (b) alkyl copper halides (c) alkanes (d) alkenyl halides

Tertiary alkyl halides are practically inert to substitution by \(S_{N^{2}}\) mechanism because of \([\mathbf{2 0 0 5}]\) (a) insolubility (b) instability (c) inductive effect (d) steric hindrance

Reaction of trans-2-phenyl-1-bromocyclopentane on reaction with alcoholic KOH produces [2006] (a) 4 -phenylcyclopentene (b) 2 -phenylcyclopentene (c) 1-phenylcyclopentene (d) 3 -phenylcyclopentene

In the following chemical reactions: \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{NH}_{2}+\mathrm{CHCl}_{3}+3 \mathrm{KOH} \longrightarrow(\mathrm{A})+(\mathrm{B})+3 \mathrm{H}_{2} \mathrm{O}\) the compounds (A) and (B) are respectively [2007] (a) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CONH}_{2}\) and \(3 \mathrm{KCl}\) (b) \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NC}\) and \(\mathrm{K}_{2} \mathrm{CO}_{3}\) (c) \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NC}\) and \(3 \mathrm{KCl}\) (d) \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{CN}\) and \(3 \mathrm{KCl}\)

The organic chloro compound, which shows complete stereochemical inversion during a \(\mathrm{SN}^{2}\) reaction, is [2008] (a) \(\left(\mathrm{C}_{2} \mathrm{H}_{3}\right)_{2} \mathrm{CHCl}\) (b) \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CCl}\) (c) \(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHCl}\) (d) \(\mathrm{CH}_{3} \mathrm{Cl}\)

Which of the following on heating with aqueous KOH, produces acetaldehyde? \([\mathbf{2 0 0 9}]\) (a) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{Cl}\) (b) \(\mathrm{CH}_{2} \mathrm{ClCH}_{2} \mathrm{Cl}\) (c) \(\mathrm{CH}_{3} \mathrm{CHCl}_{2}\) (d) \(\mathrm{CH}_{3} \mathrm{COCl}\)

Compound (A), \(\mathrm{C}_{\mathrm{s}} \mathrm{H}_{9} \mathrm{Br}\), gives a white precipitate when warmed with alcoholic \(\mathrm{AgNO}_{3}\). Oxidation of (A) gives an acid (B), \(\mathrm{C}_{8} \mathrm{H}_{6} \mathrm{O}_{4}\). (B) easily forms anhydride on heating. Identify the compound (A).

In \(\mathrm{S}_{\mathrm{N}}^{2}\) reactions, the correct order of reactivity for the following compounds: \(\mathrm{CH}_{3} \mathrm{Cl}, \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{Cl}\), \(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHCl}\) and \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CCl}\) is: \([2014]\) (a) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{Cl}>\mathrm{CH}_{3} \mathrm{Cl}>\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHCl}>\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CCl}\) (b) \(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHCl}>\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{Cl}>\mathrm{CH}_{3} \mathrm{Cl}>\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CCl}\) (c) \(\mathrm{CH}_{3} \mathrm{Cl}>\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHCl}>\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{Cl}>\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CCl}\) (d) \(\mathrm{CH}_{3} \mathrm{Cl}>\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{Cl}>\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHCl}>\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CCl}\)

The synthesis of alkyl fluorides is best accomplished by [2015] (a) Free radical fluorination (b) Sandmeyer's reaction (c) Finkelstein reaction (d) Swarts reaction