42Alcohol, Phenol and Ether

📚
INTRODUCTION
▢ Alcohols: Organic compounds containing hydroxyl group \((-OH)\) attached to saturated carbon atom.
▢ Important Outline:
  1. Classification
  2. Nomenclature
  3. Isomerism
  4. Preparation
  5. Properties
  6. Distinction of 1°, 2° and 3° alcohols
▢ Oxidation Relation:
  • •
    1° alcohol \(\rightarrow\) aldehyde \(\rightarrow\) carboxylic acid
  • •
    2° alcohol \(\rightarrow\) ketone
  • •
    3° alcohol \(\rightarrow\) resistant to oxidation in neutral/alkaline medium
📚
PREPARATION OF ALCOHOLS
▢ Oxidation of Methane:

Table 1: Controlled oxidation of methane

Condition / catalyst
Product
Air + Cu
Methanol \((CH_3OH)\)
Air + molybdenum oxide \((MoO)\)
Methanal / formaldehyde \((HCHO)\)
Air + manganese acetate \((Mn(OCOCH_3)_2)\)
Methanoic acid / formic acid \((HCOOH)\)
▢ From Alkenes:
❖ Indirect Hydration with \(98\%\ H_2SO_4\):
  • •
    Alkene + conc. \(H_2SO_4\) \(\rightarrow\) alkyl hydrogen sulphate.
  • •
    Alkyl hydrogen sulphate + boiling water \(\rightarrow\) alcohol.
  • •
    Overall process = addition of water to double bond.
  • •
    Follows Markovnikov's rule.
  • •
    Rearrangement may occur.
  • •
    Industrial method because alkenes are obtained from petroleum cracking.
  • •
    Except ethyl alcohol, no other 1° alcohol is prepared by this method.
❖ Direct Catalytic Hydration:
  • •
    Alkene directly hydrated in presence of dilute acids.
  • •
    Ethylene + steam under pressure over \(Al_2O_3\) or \(H_3PO_4\) on silica at \(300^\circ C\) gives ethanol.
❖ Oxymercuration-Demercuration:
  • •
    Reagents: \((CH_3COO)_2Hg\), THF; then \(NaBH_4/OH^-\).
  • •
    Follows Markovnikov's rule.
  • •
    No rearrangement.
  • •
    Fast and convenient.
  • •
    Mild conditions.
  • •
    Excellent yield, usually above \(90\%\).
❖ Hydroboration-Oxidation:
  • •
    Indirect addition of water.
  • •
    Reagents: \(B_2H_6\), then alkaline \(H_2O_2/NaOH\).
  • •
    Follows anti-Markovnikov's rule.
  • •
    No rearrangement.
  • •
    Best method for preparation of alcohols from alkenes.
❖ Oxo Process / Carbonylation / Hydroformylation:
  • •
    Alkene + water gas \((CO+H_2)\) gives aldehyde.
  • •
    Aldehyde on reduction gives alcohol.
▢ From Haloalkanes:
  • •
    Hydrolysis of haloalkanes with aqueous alkali.
  • •
    Reagents: aq. \(KOH\), aq. \(NaOH\), moist silver oxide \((AgOH)\).
  • •
    \(R-X + OH^- \rightarrow R-OH + X^-\)
▢ From Grignard Reagent:

Table 1: Alcohols from Grignard reagent

Carbonyl compound
Product after \(RMgX\) + hydrolysis
Formaldehyde
1° alcohol
Aldehyde except formaldehyde
2° alcohol
Ketone
3° alcohol
▢ By Reduction of Carbonyl Compounds:
❖ Reducing Agents:
  • •
    \(H_2/Ni\), \(H_2/Pd\), \(H_2/Pt\)
  • •
    \(LiAlH_4\)
  • •
    \(NaBH_4\)
  • •
    \(Na/C_2H_5OH\) = Bouveault-Blanc reduction
  • •
    \(Zn/HCl\)
  • •
    \(NaH\) = Darzens reduction
  • •
    \(NaOBr\)
❖ Products:
  • •
    Aldehyde reduction \(\rightarrow\) 1° alcohol.
  • •
    Ketone reduction \(\rightarrow\) 2° alcohol.
  • •
    3° alcohol cannot be prepared by reduction of carbonyl compounds.
▢ By Reduction of Carboxylic Acids and Derivatives:
  • •
    Carboxylic acids and acid derivatives generally give 1° alcohol on reduction.
  • •
    Exception: amide gives amine on reduction.
  • •
    \(LiAlH_4\) reduces acids and all acid derivatives.
  • •
    \(NaBH_4\) reduces only acid chloride among acid derivatives in given note.
  • •
    Acids and acid derivatives form only 1° alcohols.
  • •
    Reduction of aldehyde, ketone and ester with sodium + alcohol is called Bouveault-Blanc reduction.
▢ By Hydrolysis of Ethers:
  • •
    Ether + dilute \(H_2SO_4\) \(\rightarrow\) alcohols.
▢ By Hydrolysis of Esters:
❖ Alkaline Hydrolysis:
  • •
    Ester + aq. \(NaOH\) \(\rightarrow\) alcohol + sodium carboxylate.
  • •
    Also called saponification.
  • •
    Nucleophilic substitution reaction.
  • •
    Order of reaction = 2.
❖ Acid Hydrolysis:
  • •
    Ester + water / acid \(\rightleftharpoons\) alcohol + carboxylic acid.
  • •
    Reversible reaction.
  • •
    Order = 1.
  • •
    Pseudo-unimolecular reaction.
▢ From Aliphatic 1° Amines:
  • •
    Aliphatic 1° amines + nitrous acid \((HNO_2)\) give 1° alcohol.
  • •
    \(HNO_2\) prepared from \(NaNO_2+HCl\).
  • •
    \(CH_3CH_2NH_2 \xrightarrow{HNO_2} CH_3CH_2OH + N_2 + H_2O\).
  • •
    Methylamine gives methyl nitrite or dimethyl ether in excess nitrous acid.
  • •
    Aniline gives benzene diazonium chloride under similar conditions.
▢ From Water Gas:
  • •
    Methanol is industrially prepared by reduction of water gas.
  • •
    Catalyst: \(ZnO + Cr_2O_3\).
  • •
    Condition: high temperature and pressure.
  • •
    \(CO + 2H_2 \rightarrow CH_3OH\).
▢ Fermentation of Carbohydrates:
  • •
    Ethanol prepared by fermentation of starch.
  • •
    Ethanol prepared by fermentation of molasses/sucrose.
📚
PHYSICAL PROPERTIES
▢ General:
  • •
    Lower alcohols are generally colourless liquids.
  • •
    Alcohols form hydrogen bonds due to \(-OH\) group.
  • •
    Lower alcohols are soluble in water.
  • •
    Solubility decreases with increase in molecular mass / alkyl group size.
  • •
    Boiling point is higher than corresponding hydrocarbons and ethers due to hydrogen bonding.
📚
CHEMICAL PROPERTIES
▢ Reactions Due to Cleavage of \(O-H\) Bond:
❖ Reaction with Active Metals:
  • •
    Shows weak acidic nature.
  • •
    Alcohol + active metal \(\rightarrow\) alkoxide + hydrogen.
  • •
    \(2ROH + 2Na \rightarrow 2RONa + H_2\).
❖ Esterification with Carboxylic Acid:
  • •
    Alcohol + carboxylic acid \(\rightarrow\) ester + water.
  • •
    Catalyst: conc. \(H_2SO_4\) or dry HCl gas.
  • •
    Reversible reaction.
  • •
    Conc. \(H_2SO_4\) acts as acid catalyst and dehydrating agent.
  • •
    Dry HCl catalysed esterification = Fischer-Speier esterification.
  • •
    Water is removed to drive equilibrium forward.
  • •
    Rate of esterification \(\propto \frac{1}{steric\ hindrance}\).
❖ Rate of Esterification:

Table 1: Esterification reactivity

Case
Decreasing order
Alcohol
\(CH_3OH > C_2H_5OH > (CH_3)_2CHOH > (CH_3)_3COH\)
Carboxylic acid
\(HCOOH > CH_3COOH > (CH_3)_2CHCOOH > (CH_3)_3CCOOH\)
❖ Acylation with Acid Chlorides and Anhydrides:
  • •
    Alcohol reacts with acid chloride or acid anhydride to form ester.
  • •
    Reaction called acylation.
  • •
    With acetyl chloride/acetic anhydride → acetylation.
  • •
    With benzoyl chloride → benzoylation.
  • •
    Acetylation carried out in pyridine or dimethylaniline to remove acid formed.
❖ Inorganic Esterification:
  • •
    Alcohols react with inorganic acids except halogen acids to form inorganic esters.
  • •
    \(C_2H_5OH + H_2SO_4 \rightarrow C_2H_5OSO_3H + H_2O\)
  • •
    \(C_2H_5OH + HNO_3 \rightarrow C_2H_5ONO_2 + H_2O\)
❖ Reaction with Grignard Reagent:
  • •
    Alcohol reacts with Grignard reagent due to acidic hydrogen.
  • •
    \(ROH + R'MgX \rightarrow R'H + ROMgX\).
❖ Reaction with Diazomethane:
  • •
    Alcohols undergo alkylation with diazomethane in suitable conditions.
▢ Reactions Due to Cleavage of \(C-OH\) Bond:
❖ With Halogen Acids:
  • •
    Alcohol + HX \(\rightarrow\) alkyl halide + water.
  • •
    Reactivity generally follows: 3° alcohol > 2° alcohol > 1° alcohol.
❖ With Phosphorus Halides:
  • •
    Alcohols react with \(PCl_3\), \(PCl_5\), \(PBr_3\) to form alkyl halides.
❖ With Thionyl Chloride:
  • •
    Alcohol + \(SOCl_2\) \(\rightarrow\) alkyl chloride.
  • •
    By-products \(SO_2\) and HCl escape as gases.
❖ With Ammonia:
  • •
    Alcohol + ammonia passed over alumina at \(250^\circ C\) gives amine.
  • •
    Dehydration occurs.
❖ With Halogen:
  • •
    Oxidation and chlorination may take place simultaneously.
▢ Reactions Involving Complete Molecule:
❖ Catalytic Dehydrogenation with Copper:

Table 1: Action of Cu at 300°C

Alcohol type
Product
Example
1° alcohol
Aldehyde
\(CH_3CH_2OH \xrightarrow{Cu/300^\circ C} CH_3CHO + H_2\)
2° alcohol
Ketone
\((CH_3)_2CHOH \xrightarrow{Cu/300^\circ C} CH_3COCH_3 + H_2\)
3° alcohol
Alkene
\((CH_3)_3COH \xrightarrow{Cu/300^\circ C} (CH_3)_2C=CH_2 + H_2O\)
❖ Dehydration of Alcohols:
  • •
    Alcohol dehydration gives alkene.
  • •
    Ease of dehydration: 3° alcohol > 2° alcohol > 1° alcohol > \(CH_3OH\).
  • •
    Reason: carbocation stability 3° > 2° > 1°.
  • •
    Follows Saytzeff's rule.
  • •
    Example: 2-butanol gives mainly 2-butene and minor 1-butene.
  • •
    3° > 2° > 1° due to carbocation intermediate.
❖ Dehydration by \(H_2SO_4\):

Table 1: Ethanol with sulphuric acid

Temperature
Product
\(110^\circ C\)
Ethyl hydrogen sulphate
\(140^\circ C\)
Diethyl ether
\(170^\circ C\)
Ethene + water
❖ Dehydration by Heated Alumina:

Table 1: Ethanol over \(Al_2O_3\)

Temperature
Product
\(250^\circ C\)
Diethyl ether
\(350^\circ C\)
Ethene + water
❖ Other Dehydrating Agents:
  1. \(H_3PO_4\)
  2. \(H_2SO_4\)
  3. \(Al_2O_3\)
❖ Oxidation:
  • •
    Alcohol oxidation involves formation of C=O by cleavage of \(O-H\) and \(C-H\) bonds.
  • •
    Also called dehydrogenation reaction.
❖ Formation of Alcoholates:
  • •
    Lower alcohols react with anhydrous \(CaCl_2\), \(MgCl_2\), \(CuSO_4\) to form solid alcoholates.
  • •
    \(MgCl_2 + 6C_2H_5OH \rightarrow MgCl_2\cdot6C_2H_5OH\)
  • •
    \(CaCl_2 + 4CH_3OH \rightarrow CaCl_2\cdot4CH_3OH\)
  • •
    \(CuSO_4 + 2C_2H_5OH \rightarrow CuSO_4\cdot2C_2H_5OH\)
  • •
    Alcohols cannot be dried over anhydrous \(CaCl_2\) or \(MgCl_2\).
❖ Reaction with Bleaching Powder:
  • •
    Ethyl alcohol + bleaching powder on heating gives chloroform.
  • •
    Steps: oxidation → chlorination → hydrolysis.
  • •
    \(CH_3CH_2OH \xrightarrow{CaOCl_2} CH_3CHO\)
  • •
    \(2CH_3CHO + 6CaOCl_2 \rightarrow 2CCl_3CHO + 3Ca(OH)_2 + 3CaCl_2\)
  • •
    \(2CCl_3CHO + Ca(OH)_2 \rightarrow 2CHCl_3 + (HCOO)_2Ca\)
📚
DISTINCTION BETWEEN PRIMARY, SECONDARY AND TERTIARY ALCOHOLS
▢ Action of Heated Copper:

Table 1: Cu / 300°C test

Alcohol
Observation / product
1° alcohol
Aldehyde
2° alcohol
Ketone
3° alcohol
Alkene
▢ Oxidation:
❖ Oxidizing Agents:
  • •
    Acidic, neutral and alkaline \(KMnO_4\)
  • •
    Acidic \(K_2Cr_2O_7\)
  • •
    Dilute \(HNO_3\)

Table 1: Oxidation of alcohols

Alcohol type
Oxidation behaviour
1° alcohol
Easily oxidized to aldehydes and then acids with same number of carbon atoms.
2° alcohol
Easily oxidized to ketones with same number of carbon atoms.
3° alcohol
Resistant in neutral/alkaline \(KMnO_4\); oxidized in acidic medium to mixture of ketone and acid with fewer carbon atoms.
❖ Tertiary Alcohol Note:
  • •
    3° alcohol lacks α-hydrogen.
  • •
    Oxidation under acidic condition occurs via alkene formed by dehydration.
  • •
    Unsymmetrical ketone cleavage follows Popoff's rule.
▢ Lucas Test:
  • •
    Lucas reagent = equimolar anhydrous \(ZnCl_2\) + conc. HCl.
  • •
    3° alcohol gives turbidity immediately.
  • •
    2° alcohol gives turbidity after few minutes.
  • •
    1° alcohol gives no turbidity at room temperature / very slow reaction.
▢ Victor Meyer Test:

Table 1: Victor Meyer colour test

Alcohol type
Final observation
1° alcohol
Blood red colour
2° alcohol
Blue colour
3° alcohol
No colour
📚
READ AND DIGEST
▢ Alcohol Names and Mixtures:
  • •
    Wood spirit = methyl alcohol \((CH_3OH)\).
  • •
    Methanol obtained by destructive distillation of wood.
  • •
    Drinking methanol causes blindness.
  • •
    Liquor poisoning deaths mainly due to methyl alcohol.
  • •
    Grain alcohol = ethyl alcohol \((C_2H_5OH)\).
  • •
    Methylated spirit / denatured spirit = ethyl alcohol containing 5–10% methyl alcohol.
  • •
    Methylated spirit contains nearly 80–85% ethanol.
  • •
    Proof spirit = alcohol + water containing 57% alcohol by volume or 49.3% alcohol by weight.
  • •
    More alcohol than proof spirit = over proof spirit.
  • •
    Less alcohol than proof spirit = under proof spirit.
  • •
    Rectified spirit = 95.87% ethyl alcohol + 4.13% water.
  • •
    Absolute alcohol = 100% ethanol.
  • •
    Absolute alcohol prepared from rectified spirit by azeotropic distillation.
  • •
    Power alcohol = 80% petrol + 20% absolute ethanol + benzene as co-solvent.
  • •
    Power alcohol used to run automobiles.
  • •
    Pyroligneous acid contains acetic acid 10%, methyl alcohol 2.5%, acetone 0.5%.
  • •
    Tincture of iodine = 2–3% alcoholic solution of iodine.
▢ Oxidation and Dehydrogenation:
  • •
    Primary alcohols oxidized to aldehyde stage by Collin's reagent or PCC in anhydrous medium.
  • •
    Collin's reagent = \(CrO_3\cdot2C_5H_5N\).
  • •
    PCC = pyridinium chlorochromate.
  • •
    Acidified \(K_2Cr_2O_7\) changes orange to green due to formation of \(Cr_2(SO_4)_3\).
  • •
    3° alcohols resist oxidation due to lack of α-hydrogen.
  • •
    1° alcohol + red hot Cu → aldehyde.
  • •
    2° alcohol + red hot Cu → ketone.
  • •
    3° alcohol + red hot Cu → alkene.
▢ Esterification:
  • •
    Fischer-Speier esterification: \(CH_3COOH + C_2H_5OH \xrightarrow{dry\ HCl} CH_3COOC_2H_5 + H_2O\).
  • •
    Esterification rate useful for distinction of 1°, 2°, 3° alcohols.
  • •
    Percentage ester with acetic acid: 1° = 45.7%, 2° = 5.4%, 3° = 1.4%.
  • •
    Reactivity order: 1° > 2° > 3°.
  • •
    Water formed during esterification removed by Dean-Stark apparatus.
  • •
    Bulkier acid/alcohol → slower esterification due to steric hindrance.
▢ Dehydration and Drying:
  • •
    Alcohols cannot be dried over anhydrous \(CaCl_2\) or \(MgCl_2\) because alcoholates form.
  • •
    \(Al_2O_3\), \(H_2SO_4\), \(H_3PO_4\) act as dehydrating agents for alcohols.
  • •
    Traces of water from ethanol can be removed by reacting with Mg.
▢ Beverage Ethanol Percentages:

Table 1: Alcoholic beverages

Beverage
Source / ethanol percentage
Beer
Barley; 3–5% ethanol
Cider
Apple juice; 3–6% ethanol
Port and sherry
Grape wines; 15–20% ethanol
Whisky, brandy, rum, gin
40–50% ethanol
▢ Phenols and Polyhydric Alcohols:
  • •
    Aqueous solution of phenol = carbolic acid.
  • •
    Salol is used as intestinal antiseptic.
  • •
    Ethylene glycol = dihydroxy alcohol.
  • •
    Glycerol = trihydroxy alcohol.
  • •
    Glycerol + \(KHSO_4\) on heating gives acrolein.
📚
HIGH-YIELD REACTION SUMMARY

Table 1: Important alcohol reactions

Reaction
Reagent / condition
Product / point
Alkene → alcohol
98% \(H_2SO_4\), then water
Markovnikov alcohol; rearrangement possible
Alkene → alcohol
\((CH_3COO)_2Hg/THF\), then \(NaBH_4/OH^-\)
Markovnikov alcohol; no rearrangement
Alkene → alcohol
\(B_2H_6\), then \(H_2O_2/NaOH\)
Anti-Markovnikov alcohol; no rearrangement
Haloalkane → alcohol
Aq. \(KOH/NaOH\)
Nucleophilic substitution
Aldehyde → alcohol
\(LiAlH_4\), \(NaBH_4\), \(H_2/Ni\)
1° alcohol
Ketone → alcohol
\(LiAlH_4\), \(NaBH_4\), \(H_2/Ni\)
2° alcohol
Carboxylic acid → alcohol
\(LiAlH_4\)
1° alcohol
Ester → alcohol
\(LiAlH_4\) or \(Na/C_2H_5OH\)
Bouveault-Blanc reduction
1° amine → alcohol
\(HNO_2\)
1° alcohol + \(N_2\)
Methanol industrial synthesis
Water gas + \(ZnO/Cr_2O_3\)
\(CH_3OH\)
Alcohol + active metal
Na/K
Alkoxide + \(H_2\)
Alcohol + acid
Conc. \(H_2SO_4\) / dry HCl
Ester
Alcohol + acid chloride
Pyridine
Ester / acylation
Alcohol + Cu
\(300^\circ C\)
1° → aldehyde; 2° → ketone; 3° → alkene
Alcohol dehydration
Conc. \(H_2SO_4\), heat
Alkene / ether depending on temperature
Ethanol + bleaching powder
Heat
Chloroform
Q1.
Which of the following when reacted with water produces phenol?
📅IOM 2007
Q2.
Reduction of aldehyde gives
📅IOM 2001
Q3.
Percentage of water in absolute alcohol is
Q4.
Alcohol poisoning occurs due to the presence of .... in alcohol that is used for drinking.
📅IOM 2005
Q5.
The reactivity of alcohol with Lucas reagent follows the order
📅MOE 2008
Q6.
When ethyl alcohol is treated with acidified potassium dichromate it forms acetaldehyde. It is an example of
📅MOE 2064 Aswin
Q7.
Which enzyme is used during the production of alcohol from carbohydrate by fermentation?
📅MOE 2064
Q8.
Hydrolysis of table sugar produces
📅MOE - Curriculum
Q9.
Which of the following alcohol is most reactive towards Lucas reagent?
📅Bangladesh Embassy
Q10.
1°, 2° and 3° alcohols are distinguished by all of the following methods except
📅IOM 2051
Q11.
2C₂H₅OH + 2Na → 2C₂H₅ONa + H₂. The above reaction shows
📅IOM 2053
Q12.
Glycerol contains ......... alcoholic group.
📅TOM 2046
Q13.
Grignard reagent is
Q14.
Methylamine when treated with HNO₂ results into
📅MOE 2054
Q15.
On passing ethene through alkaline solution of KMnO₄ (Baeyer's reagent) the compound formed is
📅IOM 205
Q16.
Primary, secondary and tertiary alcohol are distinguished by
📅IOM 2052
Q17.
Reaction between NaOH and fat is called
Q18.
RCHO reacts with RMgBr and the product of hydrolysis yields
📅IOM 2046
Q19.
The alkaline solution of 1% KMnO₄ is called
📅MOE 2053
Q20.
Conversion of glucose or fructose into ethyl alcohol is brought about by
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📚
PHENOL
Q1.
When -OH group is linked with benzene, the compound formed is
📅IOM 2000
Q2.
Which of the following compound when reacted with water produces Phenol?
📅IOM 2007
Q3.
Phenol on distillation with zinc dust gives
📅IOM•MOE
Q4.
Phenol reacts with PCl₅ to give mainly
📅OM
Q5.
Phenol reacts with Br₂ in CCl₄ at low temperature gives
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📚
ETHER
Q1.
When ethyl hydrogen sulphate is heated with excess of alcohol at 410 K, the product obtained is
Q2.
Anisole with conc. HNO₃ and conc. H₂SO₄ gives
Q3.
When a 1° alkyl halide reacts with an alkoxide, the product is
Q4.
Which of the following cannot be prepared by using Williamson's synthesis?
Q5.
Which of the following compounds is resistant to nucleophilic attack by OH⁻ ions?
Q6.
How many isomeric ethers are represented by the molecular formula C₄H₁₀O?
Q7.
In Williamson synthesis, ethoxyethane is prepared by
Q8.
An aromatic ether is not cleaved by HI even at 525 K. The compound is
Q9.
Ether is obtained from ethyl alcohol
Q10.
Acetic anhydride reacts with diethyl ether in the presence of anhydrous AlCl₃ to give
Q11.
Which of the following compounds on boiling with alkaline KMnO₄ and subsequent acidification will not give benzoic acid?
Q12.
An organic compound of molecular formula C₃H₆O does not produce any precipitate with 2,4-dinitrophenylhydrazine and does not react with sodium metal. This compound is
Q13.
The C−O−C angle in ether is about
Q14.
The ether that undergoes electrophilic substitution reactions is
Q15.
Anisole with HNO₃ and conc. H₂SO₄ gives
Q16.
Ether which is liquid at room temperature is
Q17.
An ether is more volatile than an alcohol having the same molecular formula. This is due to
Q18.
When methyl-tert-butyl ether is formed?
Q19.
Alcohols are isomeric with
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Q20.
Williamson's synthesis is an example of
Q21.
Which of the following process is used in the preparation of ether?
📅MOE
Q22.
Williamson's synthesis is used to prepare
📅MOE
Q23.
Ethers on hydrolysis give
Q24.
Ethers can be used as
Q25.
Heating methyl phenyl ether with HI gives
Q26.
Higher homologues of ether can be prepared by
Q27.
Which reagent will convert >C=O group into >C(C6H5)OH?
Q28.
Which of the following compounds contains intramolecular hydrogen bonding?
Q29.
Cumene is used for commercial preparation of phenol. Chemically, cumene is
Q30.
X on heating with water above 30°C gives phenol as one product. X can be
Q31.
Oxygen passed through ethereal solution of phenyl magnesium iodide followed by acid hydrolysis gives
Q32.
Decarboxylation of sodium salicylate with soda lime forms
Q33.
When salicylic acid is heated with zinc dust, the main product is
Q34.
Reaction of phenol with formaldehyde in acid or base medium to give hydroxymethyl phenol is called
Q35.
Phenol on treatment with concentrated HNO3 and H2SO4 gives
Q36.
Which of the following reactions will produce anisole?
Q37.
In the sequence phenol → benzene → toluene → benzoic acid → sodium benzoate → Z, using soda lime in the last step, Z is
Q38.
Which reagent reacts with phenol to produce phenolphthalein?
Q39.
When ethyl iodide reacts with sodium phenolate, the product formed is
Q40.
To obtain 2-hydroxybenzaldehyde from phenol, the required reagent is
Q41.
When phenol reacts with PCl5 in presence of pyridine, the main product is
Q42.
Which compound is predominantly formed when phenol reacts with bromine water?
Q43.
In a reaction sequence where the starting compound on heating with zinc dust gives benzene, the starting compound A is
Q44.
The most acidic compound among the following is
Q45.
Which compound gives effervescence with sodium carbonate?
Q46.
Which reagent produces salicylic acid from sodium phenoxide under suitable conditions?
Q47.
Phenol reacts with CCl4 and NaOH to give mainly
Q48.
Among o-nitrophenol, p-nitrophenol and m-nitrophenol, the most acidic is
Q49.
Phenol on oxidation with K2S2O8/KOH gives
Q50.
An organic compound C7H8O dissolves in NaOH, gives colour with FeCl3 and brominated product. The compound is likely
Q51.
The hybrid state of carbon to which phenolic -OH group is attached in phenol is
Q52.
The intestinal antiseptic salol is correctly represented as
Q53.
Which of the following represents an aromatic alcohol?
Q54.
Phloroglucinol is
Q55.
An aromatic compound has molecular formula C7H8O. The number of phenolic isomers is
Q56.
Styphnic acid is
Q57.
In the sequence benzene → benzenesulphonic acid → sodium benzenesulphonate → C, the product C is
Q58.
Which of the following is stronger acid than phenol?
Q59.
Which one of the following gives a solution with pH less than 7 in water?
Q60.
Four hydroxy compounds have groups X: -CH2OH, Y: -CHOH, Z: Ph-OH, W: Ph-CH2OH. Purple colour with FeCl3 is given by
Q61.
Between p-nitrophenol and p-cresol, solubility is
Q62.
The antipyretic 2-acetoxybenzoic acid is obtained when
Q63.
The compound that fails to give effervescence with NaHCO3 is
Q64.
The unstable compound CH3CH(OH)2 changes into which compound without any reagent?
Q65.
Phenyl acetate on heating with anhydrous AlCl3 gives
Q66.
The usual acidity order among p-nitrophenol, phenol and cresol is
Q67.
Identify product Z in the reaction of phenol with CO2 at 4-7 atm and 410 K followed by acidification
Q68.
Phenyl magnesium bromide reacts with acetaldehyde followed by hydrolysis to give
Q69.
Phenol on exposure to air produces red colour due to formation of
Q70.
Reaction between phenol and benzenediazonium chloride in slightly alkaline medium at 273-278 K to give azo dye is called
Q71.
p-Phenolsulphonic acid is obtained as major product when phenol is treated with
Q72.
When o-phenolsulphonic acid is heated to 373 K, it gives
Q73.
Which reagent cannot be used to distinguish between phenol and benzyl alcohol?
Q74.
Phenol reacts with acetyl chloride in aqueous NaOH to give phenyl acetate. This reaction is an example of
Q75.
Phenol on treatment with concentrated HNO3 gives
Q76.
Salol is prepared from
Q77.
Salol can be used as
Q78.
Phenol heated with CCl4 and alkaline KOH gives salicylic acid. The reaction is known as
Q79.
The strongest acid among the following is
Q80.
Benzyl alcohol is obtained from benzaldehyde by
Q81.
To get Bakelite from phenol, the required reagent is
Q82.
Phenol is more readily soluble in
Q83.
Aspirin is also known as
Q84.
Carbolic acid is
Q85.
Which compound is known as oil of wintergreen?
Q86.
Which of the following is most acidic?
Q87.
Picric acid is
Q88.
Phenol treated with bromine water gives white precipitate of
Q89.
Which is more acidic?
Q90.
The compound used to manufacture phenol is
Q91.
Organic acid without a carboxylic acid group is
Q92.
Neutral FeCl3 gives purple colour with
Q93.
Phenol can be distinguished from ethanol by the following reagents except
Q94.
Reimer-Tiemann reaction involves
Q95.
With oxalic acid, glycerol at 503 K gives
Q96.
Chemical name of salol is
Q97.
Phenol on reduction with H2 in presence of nickel catalyst gives
Q98.
Dow's reaction involves
Q99.
Carbolic acid is
Q100.
Aspirin is an acetylation product of
Q101.
When 2-hydroxybenzoic acid is distilled with zinc dust, it gives
Q102.
Which statement is incorrect?