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🧪 NEET Chemistry❓ Question

Naming alcohols that also have a double bond, and which common name is catechol, resorcinol or hydroquinone?

Riya Singh12th Sample

14 Oct 2026 · 1 min read

I like the poetry of organic names less than I like actual poems, honestly. Naming alcohols is one more place where my marks slip away.

Question one. For CH2=CH−CH2OHCH_2=CH-CH_2OH I wrote prop-1-en-3-ol because I thought the double bond should get the lowest number as it does in alkenes. The answer key said prop-2-en-1-ol. Why does OH win over the double bond? And what about CH2=CH−CH(OH)−CH3CH_2=CH-CH(OH)-CH_3?

Question two. Dihydroxy benzenes. I know the three isomers exist (ortho, meta, para) and have trivial names catechol, resorcinol and hydroquinone, but I can never remember which is which. Also cresols, I know they are methylphenols but not their IUPAC names.

Question three. How are ethers named? I confuse "alkoxy" with "alkyl" order, and I keep forgetting anisole and phenetole.

Last, quick classification: monohydric, dihydric, trihydric, and primary, secondary, tertiary. Any trick for not mixing them?

A page of examples would be heaven.

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7 answers & replies

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  • [+]Nisha Verma12thSample· 5d ago

    OH is the principal functional group here and gets the suffix -ol, which has higher priority than a double bond. The chain has to include the carbon bearing OH, and you number so that OH gets the lowest locant. The double bond just gets its own number inside the name.

    • CH2=CH−CH2OHCH_2=CH-CH_2OH: prop-2-en-1-ol
    • CH2=CH−CH(OH)−CH3CH_2=CH-CH(OH)-CH_3: numbering from the CH3 end puts OH at 2 and the double bond at 3, so but-3-en-2-ol (the other direction would give OH at 3)
  • [+]Kabir Joshi11thSample· 5d ago

    I think double bond still has lowest number priority, since it's within the chain, and OH is just a substituent like in alkenes. So the first one is prop-1-en-3-ol like Riya wrote.

  • [+]Pooja Iyer12thSample· 5d ago

    Kabir, in a name with a suffix, the principal group (here -ol) decides numbering. Seniority order to learn: carboxylic acid > aldehyde > ketone > alcohol > amine > alkene > alkyne. The principal group gets the lowest locant; double or triple bond gets the next claim. OH is senior to C=C, so prop-2-en-1-ol is right and prop-1-en-3-ol is not a valid name.

    • [+]Kabir Joshi11thSample· 5d ago

      okay got it, -ol is the suffix so it's senior. wrote that seniority order in my notebook

  • [+]Lakshmi TripathiDropperSample· 5d ago

    Dihydroxy benzenes, with locants: catechol = benzene-1,2-diol (ortho), resorcinol = benzene-1,3-diol (meta), hydroquinone (quinol) = benzene-1,4-diol (para). Order C-R-Q matches 2-3-4 positions: Catechol 1,2, Resorcinol 1,3, Quinol 1,4.

    Cresols are methylphenols: o-cresol = 2-methylphenol, m-cresol = 3-methylphenol, p-cresol = 4-methylphenol. Other names: glycol = ethane-1,2-diol (dihydric), glycerol = propane-1,2,3-triol (trihydric).

    • [+]Riya Singh12thSample· 5d agoAuthor

      C-R-Q for 2-3-4, that's the kind of mnemonic I can keep. thanks lakshmi!

  • [+]Aman YadavDropperSample· 5d ago

    Ethers. Name as alkoxy alkane. Smaller alkyl group goes with oxygen as alkoxy, the larger is the parent chain.

    CH3OC2H5CH_3OC_2H_5: methoxyethane. C6H5OCH3C_6H_5OCH_3: methoxybenzene, anisole. C6H5OC2H5C_6H_5OC_2H_5: ethoxybenzene, phenetole.

    Primary/secondary/tertiary: count the carbons attached to the carbon carrying OH. Mono/di/tri: count OH groups. Different questions, different counting.

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