Chapter 25

When neopentyl alcohol is heated with an acid, it slowly converted into an \(85: 15\) mixture of alkenes \(\mathrm{A}\) and \(\mathrm{B}\), respectively. What are these alkenes?

The gas evolved on heating \(\mathrm{CH}_{3} \mathrm{MgBr}\) in methanol is : (a) Methane (b)Ethane (c) Propane (d) \(\mathrm{HBr}\)

The most suitable reagent for the conversion of \(\mathrm{R}-\mathrm{CH}_{2}-\mathrm{OH} \rightarrow \mathrm{R}-\mathrm{CHO}\) is: [Main 2014] (a) \(\mathrm{KMnO}_{4}\) (b) \(\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}\) (c) \(\mathrm{CrO}_{3}\) (d) PCC (Pyridinium chlorochromate)

What will be the major product when m-cresol is reacted with propargyl bromide \(\left(\mathrm{HC}^{\circ} \mathrm{C}-\mathrm{CH}_{2} \mathrm{Br}\right)\) in presence of \(\mathrm{K}_{2} \mathrm{CO}_{3}\) in acetone?

Which one of the following statements is not correct? (a) Alcohols are weaker acids than water (b) Acid strength of alcohols decreases in the following \(\mathrm{RCH}_{2} \mathrm{OH}>\mathrm{R}_{2} \mathrm{CHOH}>\mathrm{R}_{3} \mathrm{COH}\) (c) Carbon-oxygen bond length in methanol, \(\mathrm{CH}_{3} \mathrm{OH}\) is shorter than that of C - O bond length in phenol. (d) The bond angle in methanol is \(108.9^{\circ}\). COC

An unknown alochol is treated with the "Lucas reagent" to determine whether the alcohol is primary, secondary or tertiary. Which alcohol reacts fastest and by what mechanism : (a) secondary alcohol by \(\mathrm{S}_{\mathrm{N}} 1\) (b) tertiary alcohol by \(\mathrm{S}_{\mathrm{N}} 1\) (c) secondary alcohol by \(\mathrm{S}_{\mathrm{N}} 2\) (d) tertiary alcohol by \(\mathrm{S}_{\mathrm{N}} 2\)

Rate of dehydration of alcohols follows the order: (a) \(2^{\circ}>1^{\circ}>\mathrm{CH}_{3} \mathrm{OH}>3^{\circ}\) (b) \(3^{\circ}>2^{\circ}>1^{\circ}>\mathrm{CH}_{3} \mathrm{OH}\) (c) \(2^{\circ}>3^{\circ}>1^{\circ}>\mathrm{CH}_{3} \mathrm{OH}\) (d) \(\mathrm{CH}_{3} \mathrm{OH}>1^{\circ}>2^{\circ}>3^{\circ}\)

Phenol on treatment with \(\mathrm{CO}_{2}\) in the presence of \(\mathrm{NaOH}\) followed by acidification produces compound \(X\) as the major product. \(X\) on treatment with \(\left(\mathrm{CH}_{3} \mathrm{CO}\right)_{2} \mathrm{O}\) in the presence of catalytic amount of \(\mathrm{H}_{2} \mathrm{SO}_{4}\) produces :

The best method to prepare cyclohexene from cyclohexanol is by using (a) Conc. \(\mathrm{HCl}+\mathrm{ZnCl}_{2}\) (b) Conc. \(\mathrm{H}_{3} \mathrm{PO}_{4}\) (c) \(\mathrm{HBr}\) (d) Conc. HCl

The product of acid catalyzed hydration of 2 -phenylpropene is [2004S] (a) 3-phenyl-2-propanol (b) 1-phenyl-2-propanol (c) 2-phenyl-2-propanol (d) 2-phenyl-1-propanol

Allyl phenyl ether can be prepared by heating: [Main Online April 9, 2014] (a) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{Br}+\mathrm{CH}_{2}=\mathrm{CH}-\mathrm{CH}_{2}-\mathrm{ONa}\) (b) \(\mathrm{CH}_{2}=\mathrm{CH}-\mathrm{CH}_{2}-\mathrm{Br}+\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{ONa}\) (c) \(\mathrm{C}_{6} \mathrm{H}_{5}-\mathrm{CH}=\mathrm{CH}-\mathrm{Br}+\mathrm{CH}_{3}-\mathrm{ONa}\) (d) \(\mathrm{CH}_{2}=\mathrm{CH}-\mathrm{Br}+\mathrm{C}_{6} \mathrm{H}_{5}-\mathrm{CH}_{2}-\mathrm{ONa}\)

1-propanol and 2-propanol can be best distinguished by (a) oxidation with alkaline \(\mathrm{KMnO}_{4}\) followed by reaction with Fehling solution (b) oxidation with acidic dichromate followed by reaction with Fehling solution (c) oxidation by heating with copper followed by reaction with Fehling solution (d) oxidation with concentrated \(\mathrm{H}_{2} \mathrm{SO}_{4}\) followed by reaction with Fehling solution

An ether (A), \(\mathrm{C}_{5} \mathrm{H}_{12} \mathrm{O}\), when heated with excess of hot concentrated HI produced two alkyl halides which when treated with NaOH yielded compounds (B) and (C). Oxidation of (B) and (C) gave a propanone and an ethanoic acid respectively. The IUPAC name of the ether (A) is (a) 2 -ethoxypropane (b) ethoxypropane (c) methoxybutane (d) 2 -methoxybutane

The compound that will react most readily with \(\mathrm{NaOH}\) to form methanol is (a) \(\left(\mathrm{CH}_{3}\right)_{4} \mathrm{~N}^{+} \mathrm{I}^{-}\) (b) \(\mathrm{CH}_{3} \mathrm{OCH}_{3}\) (c) \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{~S}^{+} \mathrm{I}^{-}\) (d) \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CCl}\)

For the identification of \(\beta\)-naphthol using dye test, it is necessary to use [Adv. 2014] (a) Dichloromethane solution of \(\beta\)-naphthol (b) Acidic solution of \(\beta\)-naphthol (c) Neutral solution of \(\beta\)-naphthol (d) Alkaline solution of \(\beta\)-naphthol

The reaction products of \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{OCH}_{3}+\mathrm{HI} \stackrel{\Delta}{\longrightarrow}\) is : (a) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{OH}+\mathrm{CH}_{3} \mathrm{I}\) (b) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{I}+\mathrm{CH}_{3} \mathrm{OH}\) (c) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}_{3}+\mathrm{HOI}\) (d) \(\mathrm{C}_{6} \mathrm{H}_{6}+\mathrm{CH}_{3} \mathrm{OH}\)

Which of the following compounds is oxidised to prepare methyl ethyl ketone? (a) 2-Propanol (b) 1-Butanol (c) 2-Butanol (d) t-Butyl alcohol

Total number of isomers, considering both structural and stereoisomers of cyclic ethers with the molecular formula \(\mathrm{C}_{4} \mathrm{H}_{8} \mathrm{O}\) is

HBr reacts fastest with : (a) 2-methylpropan-2-ol (b) propan-1-ol (c) propan-2-ol (d) 2-methylpropan-1-ol

The reaction of phenol with benzoyl chloride to give phenyl benzoate is known as : (a) Claisen reaction (b) Schotten-Baumann reaction (c) Reimer-Tiemann reaction (d) Gatterman-Koch reaction

An industrial method of preparation of methanol is : (a) catalytic reduction of carbon monoxide in presence of \(\mathrm{ZnO}-\mathrm{Cr}_{2} \mathrm{O}_{3}\) (b) by reacting methane with steam at \(900^{\circ} \mathrm{C}\) with a nickel catalyst (c) by reducing formaldehyde with lithium aluminium hydride (d) by reacting formaldehyde with aqueous sodium hydroxide solution

The increasing order of boiling points of the below mentioned alcohols is (I) 1,2 -dihydroxybenzene (II) 1,3-dihydroxybenzene (III) 1,4-dihydroxybenzene (IV)Hydroxybenzene (a) \(\mathrm{I}<\mathrm{II}<\mathrm{IV}<\mathrm{III}\) (b) \(\mathrm{I}<\mathrm{II}<\mathrm{III}<\mathrm{IV}\) (c) \(\mathrm{IV}<\mathrm{II}<\mathrm{I}<\mathrm{III}\) (d) \(\mathrm{IV}<\mathrm{I}<\mathrm{II}<\mathrm{III}\)

The compound which reacts fastest with Lucas reagent at room temperature is (a) butan-1-ol (b) butan-2-ol (c) 2-methylpropan-1-ol (d) 2 -methylpropan-2-ol

Which of the following is basic (a) \(\mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{OH}\) (b) \(\mathrm{OH}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{OH}\) (c) \(\mathrm{H}-\mathrm{O}-\mathrm{O}-\mathrm{H}\) (d) CC(=O)O

Match the following, choosing one item from column \(\mathbf{X}\) and the appropriate item from column \(\mathbf{Y}\). [Multiple Concepts, (i) Decarboxylation (a) Addition reaction (ii) Ozonolysis (b) Soda lime (iii) Williamson's synthesis (c) Structure of alkene (iv) Dichloroethylene (d) Ether

Ethyl alcohol is heated with conc \(\mathrm{H}_{2} \mathrm{SO}_{4}\) the product formed is (a) CCOC(C)=O (b) \(\mathrm{C}_{2} \mathrm{H}_{6}\) (c) \(\mathrm{C}_{2} \mathrm{H}_{4}\) (d) \(\mathrm{C}_{2} \mathrm{H}_{2}\)

When phenol is reacted with \(\mathrm{CHCl}_{3}\) and \(\mathrm{NaOH}\) followed by acidification, salicyladehyde is obtained. Which of the following species are involved in the above mentioned reaction as intermediate?

Chlorination of toluene in the presence of light and heat followed by treatment with aqueous \(\mathrm{NaOH}\) gives (a) \(o\)-Cresol (b) \(p\)-Cresol (c) 2,4 -Dihydroxytoluene (d) Benzoic acid

Phenol reacts with bromine in carbon disulphide at low temperature to give (a) \(m\)-bromophenol (b) \(o\) - and \(p\)-bromophenol (c) \(p\)-bromophenol (d) \(2,4,6\)-tribromophenol

When phenol is treated with excess bromine water, it gives: (a) \(m\)-Bromophenol (b) \(o\) - and \(p\)-Bromophenol (c) 2 , 4-Dibromophenol (d) 2,4, 6-Tribromophenol

2,2 -Dimethyloxirane can be cleaved by acid \(\left(\mathrm{H}^{+}\right)\). Write mechanism.

Glycerine contains one ................... hydroxy group.

Which of the following is the correct method for synthesising methylt-butyl ether and why? (i) \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CBr}+\mathrm{NaOMe} \rightarrow\) (ii) \(\mathrm{CH}_{3} \mathrm{Br}+\mathrm{NaO}-\mathrm{t}-\mathrm{Bu} \rightarrow\)

An organic compound containing \(\mathrm{C}, \mathrm{H}\) and \(\mathrm{O}\) exists in two isomeric forms \(\mathrm{A}\) and \(\mathrm{B}\). An amount of \(0.108 \mathrm{~g}\) of one of the isomers gives on combustion \(0.308 \mathrm{~g}\) of \(\mathrm{CO}_{2}\) and \(0.072 \mathrm{~g}\) of \(\mathrm{H}_{2} \mathrm{O} . \mathrm{A}\) is insoluble in \(\mathrm{NaOH}\) and \(\mathrm{NaHCO}_{3}\) while \(\mathrm{B}\) is soluble in \(\mathrm{NaOH}\). A reacts with conc. HI to give compounds \(C\) and D. C can be separated from D by ethanolic \(\mathrm{AgNO}_{3}\) solution and \(\mathrm{D}\) is soluble in \(\mathrm{NaOH}\). B reacts readily with bromine water to give compound \(\mathrm{E}\) of molecular formula, \(\mathrm{C}_{7} \mathrm{H}_{5} \mathrm{OBr}_{3}\). Identify, \(\mathrm{A}, \mathrm{B}, \mathrm{C}, \mathrm{D}\) and \(\mathrm{E}\) with justification and give their structures.

Give reasons for the following : Sodium metal can be used for drying diethyl ether but not ethanol.

A compound (X) containing C, H and \(\mathrm{O}\) is unreactive towards sodium. It does not add bromine. It also does not react with Schiff's reagent. On refluxing with an excess of hydriodic acid, (X) yields only one organic product (Y). On hydrolysis, (Y) yields a new compound (Z) which can be converted into (Y) by reaction with red phosphorus and iodine. The compound (Z) on oxidation with potassium permanganate gives a carboxylic acid. The equivalent weight of this acid is 60 . What are the compounds \((\mathrm{X}),(\mathrm{Y})\) and \((\mathrm{Z}) ?\) Write chemical equations leading to the conversion of \((\mathrm{X})\) to \((\mathrm{Y})\).

Formation of phenol from chlorobenzene is an example of \(\ldots \ldots \ldots \ldots . .\) aromatic substitution.

Read the following statement and explanation and answer as per the options given below : Statement (S) : Solubility of \(n\)-alcohols in water decreases with increase in molecular weight. Explanation (E) : The relative proportion of the hydrocarbon part in alcohols increases with increasing molecular weight which permits enhanced hydrogen bonding with water. (a) Both (S) and (E) are correct and (E) is the correct explanation of (S). (b) Both (S) and (E) are correct but \((\mathrm{E})\) is not the correct explanation of (S). (c) (S) is correct but (E) is wrong. (d) (S) is wrong but (E) is correct.

A biologically active compound, bombykol \(\left(\mathrm{C}_{16} \mathrm{H}_{30} \mathrm{O}\right)\) is obtained from a natural source. The structure of the compound is determined by the following reactions. (a) On hydrogenation, bombykol gives a compound A, \(\mathrm{C}_{16} \mathrm{H}_{34} \mathrm{O}\), which reacts with acetic anhydride to give an ester; (b) Bombykol also reacts with acetic anhydride to give another ester, which on oxidative ozonolysis \(\left(\mathrm{O}_{3} / \mathrm{H}_{2} \mathrm{O}_{2}\right)\) gives a mixture of butanoic acid, oxalic acid and 10 -acetoxydecanoic acid. Determine the number of double bonds in bombykol. Write the structures of compound \(\boldsymbol{A}\) and bombykol. How many geometrical isomers are possible for bombykol?

The reaction of \(\mathrm{CH}_{3} \mathrm{CH}=\mathrm{CH}\) OH with HBr gives (a) \(\mathrm{CH}_{3} \mathrm{CHBrCH}_{2}\) (b) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CHBr}\) (c) \(\mathrm{CH}_{3} \mathrm{CHBrCH}_{2}\) (d) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CHBr}\).

Give reasons for the following : Acid catalysed dehydration of \(t\)-butanol is faster than that of \(n\)-butanol.

When phenol is reacted with \(\mathrm{CHCl}_{3}\) and \(\mathrm{NaOH}\) followed by acidification, salicylaldehyde is obtained. Which of the following species are involved in the above mentioned reaction as intermediates?

An optically active alcohol \(A\left(\mathrm{C}_{6} \mathrm{H}_{10} \mathrm{O}\right)\) absorbs two moles of hydrogen per mole of \(A\) upon catalytic hydrogenation and gives a product \(B\). The compound \(B\) is resistant to oxidation by \(\mathrm{CrO}_{3}\) and does not show any optical activity. Deduce the structures of \(A\) and \(B\).

Phenol is less acidic than : (a) acetic acid (b) \(p\)-methoxyphenol (c) \(p\)-nitrophenol (d) ethanol

3,3-Dimethylbutan-2-ol loses a molecule of water in the presence of concentrated sulphuric acid to give tetramethylethylene as a major product. Suggest a suitable mechanism.

Match each item of the right hand column with an appropriate item in the left hand column for each of the following sections: A. \((i) \quad\) spinel (a) \(\mathrm{MgAl}_{2} \mathrm{O}_{4}\) (ii) feldspar (b) \(\mathrm{PbCO}\) (iii) cerussite (c) \(\mathrm{KAlSi}_{3} \mathrm{O}_{8}\) (iv) malachite (d) \(\mathrm{MgSO}_{4} \cdot \mathrm{H}_{2} \mathrm{O}\) (v) kisserite (e) \(\mathrm{Cu}(\mathrm{OH})_{2} \cdot \mathrm{CuCO}_{3}\) B. (vi) liquid air (f) Deacon process (vii) \(\mathrm{Na}_{2} \mathrm{CO}_{3}\) (g) Parke process (viii) nitric oxide (h) Claude process \((i x)\) silver (i) Ostwald process \((x)\) chlorine (j) Solvay process C. \((x i)\) phenol (k) coloured glass (xii) \(\mathrm{Na}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}\) (1) antichlor (xiii) salicylic acid (m) refractory material \((x i v)\) quick lime (n) antiseptic \((x v) \quad \mathrm{CuO}\) (o) analgesic D. \((x v i)\) Aston (p) radium \(\begin{array}{ll}\text { (xvii) Priestley } & \text { (q) radioactivity }\end{array}\) (xviii) Ramsay (r) oxygen \((x i x) \quad\) Marie Curie (s) inert gas \((x x) \quad\) Bacquerel (t) mass spectrum

When \(t\)-butanol and \(n\)-butanol are separately treated with a few drops of dilute \(\mathrm{KMnO}_{4}\), in one case only the purple colour disappears and a brown precipitate is formed. Which of the two alcohols gives the above reaction and what is the brown precipitate?

Match the following, choosing one item from column \(\mathbf{X}\) and one from column Y. \(\mathbf{X}\) \(\mathbf{Y}\) (i) pyrolysis of alkanes (a) elimination reaction (ii) benzene+chloroethane (b) saponification (+anhydrous \(\mathrm{AlCl}_{3}\) ) (iii) \(\mathrm{CH}_{3} \mathrm{COOC}_{2} \mathrm{H}_{5}\) (c) Wurtz reaction \(+\mathrm{NaOH}\) (iv) preparation of alkanes (d) Friedel-Crafts reaction (v) phenol (e) Reimer-Tiemann \(+\mathrm{CHCl}_{3}(\mathrm{NaOH})\) reaction (vi) \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{Br}+\mathrm{alc} . \mathrm{KOH}\) (f) cracking

Compound ' \(X\) ' (molecular formula, \(\mathrm{C}_{5} \mathrm{H}_{8} \mathrm{O}\) ) does not react appreciably with Lucas reagent at room temperature but gives a precipitate with ammonical silver nitrate. With excess of \(\mathrm{MeMgBr}, 0.42 \mathrm{~g}\) of \(^{‘} X\) gives \(224 \mathrm{~mL}\) of \(\mathrm{CH}_{4}\) at STP. Treatment of ' \(X\) ' with \(\mathrm{H}_{2}\) in presence of \(\mathrm{Pt}\) catalyst followed by boiling with excess HI, gives \(n\)-pentane. Suggest structure for ' \(X\) and write the equation involved.

A ketone 'A' which undergoes haloform reaction gives compound B on reduction. \(\mathrm{B}\) on heating with sulphuric acid gives compound \(\mathrm{C}\), which forms monoozonide D, D on hydrolysis in presence of zinc dust gives only acetaldehyde. Identify \(\mathrm{A}, \mathrm{B}\) and \(\mathrm{C}\). Write down the reactions involved.