Organic Compounds Containing Oxygen

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Identify the suitable reagent for the following conversion.Methyl benzoate (Ph-COOCH3) → benzaldehyde (Ph-CHO) Answer: 2. (i) AlH(iBu)₂ (ii) H₂O Key idea: partial reduction of an ester to an aldehyde needs DIBAL-H at low temperature. AlH(i-Bu)₂ follow... Aldehydes and ketones: HCN, NH3 derivatives, Grignard, oxidation, reduction (Wolff-Kishner, Clemmensen) 1 answer
The major product of the following reaction is :Reactant: Ph-CO-CH2CH2-CN; (i) CH_3MgBr (excess); (ii) H_3O^+ Answer: 2. structure (2) Key idea: Grignard reagent adds to both the ketone and the nitrile, but the nitrile adduct is hydrolysed to a keton... Aldehydes and ketones: HCN, NH3 derivatives, Grignard, oxidation, reduction (Wolff-Kishner, Clemmensen) 1 answer
The correct order of decreasing acidity of the following aliphatic acids is : Answer: 3. HCOOH > CH₃COOH > (CH₃)₂CHCOOH > (CH₃)₃CCOOH Key idea: alkyl groups are electron-donating (+I) and destabilise the carboxylate io... Carboxylic acids: acidic strength 1 answer
Which one of the following alcohols reacts instantaneously with Lucas reagent? Answer: 1. CH₃-C(CH₃)(CH₃)-OH (i.e. (CH₃)₃C-OH , drawn with CH₃ above and below the carbon) Key idea: Lucas reagent ( ZnCl₂ /conc. HCl) work... Alcohols: identification of 1/2/3 alcohols, dehydration mechanism 1 answer
Major products A and B formed in the following reaction sequence, are[scheme: 2-methylcyclohexanol (OH and H_3C on adjacent ring carbons) PBr_3 A (major) [Δ]alc.\ KOH B (major), see figure] Answer: 2. A = [structure: 1-bromo-2-methylcyclohexane], B = [structure: 1-methylcyclohexene (double bond adjacent to methyl carbon)] Key id... Alcohols: identification of 1/2/3 alcohols, dehydration mechanism 1 answer
Match List I with List II.List I (Reactions): A. [structure: bicyclohexylidene → 2 cyclohexanone] B. [structure: benzene → benzophenone] C. [structure: cyclohexanol → cyclohexanone] D. [structure: ethylbenzene → potassium benzoate]List II (Reagents/C… Answer: 4. A-IV, B-I, C-II, D-III Key idea: identify the reagent for each conversion. A: alkene to two ketones is ozonolysis, O₃ , then Zn-H... Aldehydes and ketones: HCN, NH3 derivatives, Grignard, oxidation, reduction (Wolff-Kishner, Clemmensen) 1 answer
Identify the correct reagents that would bring about the following transformation.[structure transformation shown in figure: ring-CH_2-CH=CH_2 → ring-CH_2-CH_2-CHO] Answer: 3. (i) BH₃ (ii) H₂O₂/oversetominusOH (iii) PCC Key idea: the -CH=CH₂ group must become -CH₂CH₂CHO , a terminal aldehyde, which needs... Aldehydes and ketones: HCN, NH3 derivatives, Grignard, oxidation, reduction (Wolff-Kishner, Clemmensen) 1 answer
Consider the following reaction and identify the product (P).CH_3-CH(CH_3)-CH(OH)-CH_3 (3 - Methylbutan-2-ol) HBr Product (P) Answer: 2. CH₃-C(Br)(CH₃)-CH₂-CH₃ Key idea: A secondary alcohol with HBr reacts through a carbocation ( S_N1 ), which can rearrange to a mor... Alcohols: identification of 1/2/3 alcohols, dehydration mechanism 1 answer
Which amongst the following will be most readily dehydrated under acidic conditions ? Answer: 3. skeletal structure (3) bearing two OH, H ₃ C and H (see figure) Key idea: Acid-catalysed dehydration of an alcohol goes through a... Alcohols: identification of 1/2/3 alcohols, dehydration mechanism 1 answer
Identify product (A) in the following reaction :3-(3-acetylphenyl)-substituted cyclohexyl methyl ketone: a cyclohexane ring bearing an acetyl group, joined to a benzene ring bearing an acetyl group (meta), [conc. HCl]Zn-Hg (A) + 2H_2O Answer: 2. both acetyl groups reduced to ethyl groups (structure) Key idea: Zn-Hg/conc. HCl is the Clemmensen reduction, which converts >C=O... Aldehydes and ketones: HCN, NH3 derivatives, Grignard, oxidation, reduction (Wolff-Kishner, Clemmensen) 1 answer
Consider the following reaction :C_6H_5-CH_2-O-C_6H_5 [Δ]HI A + B (benzyl phenyl ether)Identify products A and B. Answer: 4. A = C ₆ H ₅ -CH ₂ I and B = C ₆ H ₅ -OH Key idea: HI cleaves an aryl alkyl ether at the alkyl-oxygen bond, because the aryl C-O b... Ethers 1 answer
Identify the major product obtained in the following reaction :2-acetylbenzaldehyde (benzene ring with ortho -COCH_3 and -CHO) + 2[Ag(NH_3)_2]^+ + 3 ^-OH Δ major product Answer: 4. ring with -COCH ₃ and -COO ^- (structure) Key idea: Tollens' reagent [Ag(NH₃)₂]^+ in base is a mild oxidant: it oxidises aldehyde... Tests to distinguish aldehydes and ketones 1 answer
Complete the following reaction :cyclohexanone [A] HCN cyclohexanone cyanohydrin (1-hydroxycyclohexanecarbonitrile) [B] [Δ]conc.\ H_2SO_4 [C][C] is ________. Answer: 1. cyclohex-1-ene-1-carboxylic acid (structure) Key idea: Conc. H₂SO₄ with heat does two things to a cyanohydrin: it hydrolyses -CN... Aldehydes and ketones: HCN, NH3 derivatives, Grignard, oxidation, reduction (Wolff-Kishner, Clemmensen) 1 answer
Given below are two statements :Statement I :In Lucas test, primary, secondary and tertiary alcohols are distinguished on the basis of their reactivity with conc. HCl + ZnCl_2, known as Lucas Reagent.Statement II :Primary alcohols are most reactive a… Answer: 4. Statement I is correct but Statement II is incorrect. Key idea: Lucas reagent (conc. HCl + ZnCl₂ ) works via carbocation formatio... Alcohols: identification of 1/2/3 alcohols, dehydration mechanism 1 answer
Which one of the following is not formed when acetone reacts with 2-pentanone in the presence of dilute NaOH followed by heating ? Answer: 3. [structure in figure] Key idea: in crossed aldol condensation with NaOH, either ketone can give the enolate and either can be the... Alpha-hydrogen acidity, aldol, Cannizzaro, haloform 1 answer
Match List - I with List - II.List - I (Products formed): (a) Cyanohydrin (b) Acetal (c) Schiff's base (d) OximeList - II (Reaction of carbonyl compound with): (i) NH_2OH (ii) RNH_2 (iii) alcohol (iv) HCNChoose the correct answer from the options giv… Answer: 1. (a) - (iv), (b) - (iii), (c) - (ii), (d) - (i) Key idea: link each product to the reagent used with a carbonyl compound. Cyanohyd... Aldehydes and ketones: HCN, NH3 derivatives, Grignard, oxidation, reduction (Wolff-Kishner, Clemmensen) 1 answer
Given below are two statements :Statement I :The boiling points of aldehydes and ketones are higher than hydrocarbons of comparable molecular masses because of weak molecular association in aldehydes and ketones due to dipole - dipole interactions.St… Answer: 2. Both Statement I and Statement II are correct. Key idea: polarity of C=O gives dipole-dipole attraction but no hydrogen bonding b... Carbonyl group and nucleophilic addition, relative reactivity 1 answer
Given below are two statements :Statement I :The acidic strength of monosubstituted nitrophenol is higher than phenol because of electron withdrawing nitro group.Statement II :o-nitrophenol, m-nitrophenol and p-nitrophenol will have same acidic stren… Answer: 4. Statement I is correct but Statement II is incorrect. Key idea: the -NO₂ group is electron withdrawing and stabilises the phenoxi... Phenols: acidity, electrophilic substitution, Reimer-Tiemann 1 answer
RMgX + CO_2 dry ether Y H_3O^+ RCOOHWhat is Y in the above reaction ? Answer: 2. RCOO^(-M)g^+X Key idea: a Grignard reagent adds to CO₂ to give a magnesium carboxylate salt, which acid hydrolysis converts to th... Aldehydes and ketones: HCN, NH3 derivatives, Grignard, oxidation, reduction (Wolff-Kishner, Clemmensen) 1 answer
The product formed in the following chemical reaction is :2-(methyl-substituted) cyclohexanone bearing CH_2-C(=O)-OCH_3 and CH_3 groups [C_2H_5OH]NaBH_4 ? Answer: 4. Cyclohexane ring with OH, CH₃ and CH₂-C(=O)-OCH₃ substituents Key idea: NaBH₄ is a mild reducing agent. It reduces aldehydes and... Aldehydes and ketones: HCN, NH3 derivatives, Grignard, oxidation, reduction (Wolff-Kishner, Clemmensen) 1 answer
Match List - I with List - II.List - I : (a) benzene [Anhyd. AlCl_3/CuCl]CO,\ HCl (b) R-CO-CH_3 + NaOX → (c) R-CH_2-OH + R'COOH Conc. H_2SO_4 (d) R-CH_2COOH [(ii) H_2O](i) X_2/Red PList - II : (i) Hell-Volhard-Zelinsky reaction (ii) Gattermann-Koch r… Answer: 4. (a)-(ii), (b)-(iii), (c)-(iv), (d)-(i) Key idea: match each reaction with its name. (a) benzene + CO, HCl, anhydrous AlCl₃ /CuCl:... Aldehydes and ketones: HCN, NH3 derivatives, Grignard, oxidation, reduction (Wolff-Kishner, Clemmensen) 1 answer
The intermediate compound 'X' in the following chemical reaction is :toluene + CrO_2Cl_2 CS_2 X H_3O^+ benzaldehyde Answer: 1. C₆H₅-CH(OCrOHCl₂)₂ Key idea: this is the Etard reaction: toluene is partially oxidised to benzaldehyde by chromyl chloride. Tolue... Aldehydes and ketones: HCN, NH3 derivatives, Grignard, oxidation, reduction (Wolff-Kishner, Clemmensen) 1 answer
What is the IUPAC name of the organic compound formed in the following chemical reaction ?Acetone [(ii) H_2O, H^+](i) C_2H_5MgBr,\ dry Ether Product Answer: 4. 2-methyl butan-2-ol Key idea: a Grignard reagent adds to a ketone to give a tertiary alcohol. mathrm(CH₃)₂C=O+C₂H₅MgBr→(CH₃)₂C(C₂... Aldehydes and ketones: HCN, NH3 derivatives, Grignard, oxidation, reduction (Wolff-Kishner, Clemmensen) 1 answer
Anisole on cleavage with HI gives : Answer: 1. Phenol (C ₆ H ₅ OH) + CH ₃ I Aryl alkyl ethers are cleaved by HI at the alkyl-oxygen bond. The ether oxygen is protonated, then I... Ethers 1 answer

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