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Asked on 7th December

Question : Which shape of SF4 is more stable : I or II?

SF4 shape 1 : more stable

I

SF4 shape 2 : less stable

II

Answer : The structure (I) is more stable because repulsion is least when the lone pairs are at equatorial position.
Reference : Shapes of molecules are discuessed in Hybridisation.

Asked on 5th November

Practice Questions Series [#7 Carboxylic Acids] :
We shared a link that contains some important questions (and answers) on "carboxylic acids". You can study them here : Practice Questions on Carboxylic Acids.

Asked on 22nd October

Practice Questions Series [#6 Aldehydes and Ketones] :
We shared a link that contains some important questions (and answers) on "aldehydes and ketones". You can study them here : Practice Questions on Aldehydes and Ketones.

Asked on 16th October

Practice Questions Series [#5 Ethers] :
We shared a link that contains some important questions (and answers) on ethers. You can study them in Practice Questions on Ethers.

Asked on 9th October

Practice Questions Series [#4 Alcohols and Phenols] :
We shared a link that contains 15 important questions (and answers) on alcohols and phenols. You can study them in Practice Questions on Alcohols and Phenols.

Asked on 30th September

Practice Questions Series [#3 Haloalkanes & Haloarenes] :
We shared a link that contains 15 important questions (and answers) on haloalkanes and haloarenes. You can study them in Practice Questions on Haloalkanes and Haloarenes.

Asked on 19th September

Practice Questions Series [#2 Hydrocarbons] :
We shared a link that contains 15 important questions (and answers) from hydrocarbons. You can study them in Practice Questions on Hydrocarbons.

Asked on 3rd September

Practice Questions Series [#1 Fundamentals] :
We shared a link that contains 15 important questions (and answers) on fundamentals of organic chemistry. You can study them in Practice Questions on Fundamentals of Organic Chemistry.

Asked on 20th August

Question : Identify ?a, ?b and ?c.

organicmystery question answer

Answer : Study the following points :

  1. Alkyl halides undergo β-elimination with alcoholic KOH; therefore, ?a must be propene.
  2. Alkenes react with HBr in the presence of peroxides to give haloalkanes according to anti-markovnikov's rule; therefore, ?b must be bromopropane.
  3. Alkyl halides react with Na in the presence of dry ether to give alkanes with twice the number of carbon atoms present in the alkyl halide; therefore, ?c must be hexane. This reaction is known as Wurtz reaction.

Hence, the complete reaction is :

organicmystery question answer

Reference : Reaction of alkyl halides with alc. KOH is discussed in preparation of alkenes. Reaction of alkenes with HBr and anti-markovnikov's rule are discussed in reactions of alkenes. Wurtz reaction is discussed in preparation of alkanes.

Asked on 13th August

Question : Which one does not show cis-trans isomerism : CHCl═CCl2, CHCl═CHCl, CH3CH═CHCH3?

Answer : CHCl═CCl2 has identical atoms on the same side of double bond; therefore, it cannot show cis-trans isomerism.

cis-trans isomerism

Reference : Geometrical isomerism or cis-trans isomerism is explained in alkene.

Asked on 3rd August

Question : Which carbocation is the most stable and which one is the least?

Stability of carbocations

Answer : Due to hyperconjugation and inductive effect, the stability of carbocations follows the order :

(CH3)3C+   >   (CH3)2CH+   >   CH3CH2+   >   CH3+

Reference : Inductive effect and hyperconjugation are discussed in inductive and electromeric effect; and hyperconjugation respectively.

Asked on 24th July

Question : What is the IUPAC name of this compound?

Hybridisation of carbon

Answer : When a chain terminating functional group such as COOH, CHO appears more than two times in the parent chain, then their carbons are not included while numbering the parent chain. Hence, the IUPAC name of the above compound is :

Question asked on facebook

Notice that the suffix 'carboxylic acid' is used in this case and not 'oic acid'. This compound is also known as citric acid.

Reference : Such compounds are discussed in Nomenclature of Polyfunctional Compounds.

Asked on 10th July

Question : Find the hybridisation of each carbon.

Hybridisation of carbon

Answer : Hybridisation of carbon depends on the number of atoms attached to carbon :

Hybridisation − Carbon
Carbon AtomType of Hybridisation
Carbon attached to 4 atoms sp3
Carbon attached to 3 atoms sp2
Carbon attached to 2 atoms sp

Hence, the answer is :

Question asked on facebook

Reference : Hybridisation is discussed in Hybridisation.

Asked on 1st July

Question : In the following compound, there is a hydrogen bond between nitrogen and hydrogen atoms (represented by dotted lines). Do you know if the bond is intermolecular hydrogen bond or intramolecular bond.

Question asked on facebook

Answer : In intermolecular hydrogen bond, the hydrogen bond is formed between atoms of two different molecules. Example : Hydrogen bond between two different H2O molecules. In intramolecular hydrogen bond, the hydrogen bond is formed between atoms of the same molecules.

Hence, the hydrogen bond in the asked compound is intramolecular hydrogen bond.

Reference : Hydrogen bond is discussed in Hydrogen Bonding.

Asked on 25th June

Question : Do you know the IUPAC name of the following compound :

Question asked on facebook

Answer : If a compound contains a functional group then the principal chain must contain it; therefore, the principal chain in the above compound contains six carbon atoms (and not eight).

Question asked on facebook

Hence, the IUPAC name of the above compound is 2-propylhexanal.

Reference : Nomenclature of such compounds is discussed in Nomenclature of Compounds Containing One Functional Group. If you want to learn nomenclature from the very beginning, you should start from Nomenclature Introduction.