Chapter 26

Arrange the following in the order of decreasing tendency towards \(\mathrm{S}_{\mathrm{N}}^{2}\) reaction 1\. \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Cl}\) 2\. \(\mathrm{CH}_{3} \mathrm{CH}_{2}-\mathrm{CHCl}-\mathrm{CH}_{3}\) 3\. \(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHCH}_{2} \mathrm{Cl}\) 4\. \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{C}-\mathrm{Cl}\) (a) \(1>3>2>4\) (b) \(4>4>3>1\) (c) \(2>1>3>4\) (d) \(1>2>4>3\)

Which of the following order represents the increasing order of reactivity towards \(\mathrm{Br}^{-}\)under \(\mathrm{S}_{\mathrm{N}}{\underline{\phantom{xx}}}^{1}\) conditions? 1\. vinyl chloride 2\. methyl chloride 3\. ethyl chloride 4\. allyl chloride (a) \(4<3<2<1\) (b) \(1<2<3<4\) (c) \(2<1<3<4\) (d) \(2<1<4<3\)

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) \(\mathrm{BrCH}_{2} \mathrm{CH}_{2}^{2} \mathrm{Br}\) (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 \(\mathrm{KOH}\). (b) Heating with alc \(\mathrm{KOH}\) (c) Heating with dry silver oxide (d) Heating with moist silver oxide.

Match the following: List I (Reactants) 1\. \(\mathrm{CH}_{3}\left(\mathrm{CH}_{2}\right)_{3} \mathrm{OH} \frac{\mathrm{NaBr}, \mathrm{H}_{2} \mathrm{SO}_{4}, \Delta}{\longrightarrow}\) 3\. \(\mathrm{CH}_{3} \mathrm{CH}(\mathrm{OH})\left(\mathrm{CH}_{2}\right)_{2} \mathrm{CH}_{3} \stackrel{\mathrm{PBr}_{3}}{\longrightarrow}\) 4\. \(\mathrm{Me}_{2} \mathrm{CHCH}_{2} \mathrm{OH} \stackrel{\mathrm{sOC}_{3}}{\longrightarrow}\) 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 \(\begin{array}{rrrrr}1 & 2 & 3 & 4 \\ \text { (a) } \mathrm{C} & \mathrm{D} & \mathrm{B} & \mathrm{A}\end{array}\) (b) \(\mathrm{C} \quad \mathrm{D} \quad \mathrm{A} \quad \mathrm{B}\) (c) \(\mathrm{D} \quad \mathrm{C} \quad \mathrm{A} \quad \mathrm{B}\) (d) D \(\mathrm{C} \quad \mathrm{B} \quad \mathrm{A}\)

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

Match the following \begin{tabular}{ll} \hline Column-I & Column-II \\ \hline (a) Acetylsalicylic acid & (p) Insecticide \\ (b) DDT & (q) Drug \\ (c) Naphthalene & (r) Moth repellent \\ (d) Carbon tetrahcloride & (s) Fire extinguisher \\ & (t) Sublimation \end{tabular}

How many moles of alkyl halides will react with a mole of ethylamine converting it into its ammonium salt?

The compound shown below is allowed to react with \(\mathrm{H}_{2} \mathrm{O} .\) Predict the number of optically active isomers formed in the reaction. CC(Br)C(Br)CCO Optically active isomers

How many elimination products are possible when 1chloromethyl cyclopentane is treated with alcoholic \(\mathrm{KOH} ?\)

The number of \(\mathrm{H}\) - atoms that can participate when CCC(C)(Br)CC is subjected to elimination is

\(\mathrm{CH}_{3} \mathrm{MgI}\) is an organometallic compound due to \([\mathbf{2 0 0 2}]\) (a) \(\mathrm{Mg}-\mathrm{I}\) bond (b) \(\mathrm{C}-\mathrm{I}\) bond (c) C-Mg bond (d) \(\mathrm{C}-\mathrm{H}\) bond

When a primary amine reacts with chloroform in ethanolic KOH, then the product formed is [2002] (a) an aldehyde (b) an isocyanide (c) an cyanide (d) an alcohol

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 A and 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 \(\mathrm{C}_{6} \mathrm{H}_{3} \mathrm{I}\) (c) \(\mathrm{B}\) 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? (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 (a) alkenes (b) alkyl copper halides (c) alkanes (d) alkenyl halides

Tertiary alkyl halides are practically inert to substitution by \(\mathrm{S}_{\mathrm{N}^{2}}\) mechanism because of [2005] (a) insolubility (b) instability (c) inductive effect (d) steric hindrance

\(\mathrm{CH}_{3} \mathrm{Br}+\mathrm{Nu} \longrightarrow \mathrm{CH}_{3}-\mathrm{Nu}+\mathrm{Br}^{-}\) The decreasing order of the rate of the above reaction with nucleophiles \(\left(\mathrm{Nu}^{-}\right)\)(a) to \((\mathrm{d})\) is [2006] \(\left[\mathrm{Nu}^{-}=\left(\right.\right.\)a) \(\mathrm{Ph} \mathrm{O}^{-}\)(b) \(\mathrm{AcO}^{-}\)(c) \(\mathrm{HO}^{-}\)(d) \(\left.\mathrm{CH}_{3} \mathrm{O}^{-}\right]\) (a) \(4>3>1>2\) (b) \(4>3>2>1\) (c) \(1>2>3>4\) (d) \(2>4>3>1\)

Fluorobenzene \(\left(\mathrm{C}_{6} \mathrm{H}_{3} \mathrm{~F}\right)\) can be synthesized in the laboratory [2006] (a) by heating petrol with \(\mathrm{HF}\) and \(\mathrm{KF}\) (b) from aniline by diazotization followed by heating the diazonium salt with \(\mathrm{HBF}_{4}\) (c) by direct fluorination of benzene with \(\mathrm{F}_{2}\) gas (d) by reacting bromobenzene with NaF solution

Reaction of trans-2-phenyl-1-bromocyclopentane on reaction with alcoholic KOH produces (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) \(\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{2} \mathrm{CHCl}\) (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? [2009] (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) \(\mathrm{CH}_{3} \mathrm{COCl}\)

Consider the following bromides: CCC(C)Br CCCCBr C=CC(C)Br I II III The correct order of \(S_{N} 1\) reactivity is (a) \(\mathrm{II}>\mathrm{III}>\mathrm{I}\) (b) \(\mathrm{II}>\mathrm{I}>\mathrm{III}\) (c) \(\mathrm{III}>\mathrm{II}>\mathrm{I}\) (d) \(\mathrm{I}>\mathrm{II}>\mathrm{III}\)

Compound (A), \(\mathrm{C}_{8} \mathrm{H}_{9} \mathrm{Br}\), 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). [2013]

In \(\mathrm{S}_{\mathrm{N}}{\underline{\phantom{xx}}}^{2}\) 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 (a) Free radical fluorination (b) Sandmeyer's reaction (c) Finkelstein reaction (d) Swarts reaction

2-chloro-2-methyl pentane on reaction with sodium methoxide in methanol yields. (a) CCCC(C)(C)OC (b) C=C(C)CCC (c) CCC=C(C)C (a) (a) and (c) (b) c only (c) (a) and (b) (d) all of these