Practical Organic Chemistry Test - 7

The carbon atom involved in the formation of 1 π bond is sp² hybridised, and the C-atom involved in the formation of 2-π bonds is sp hybridised.
In the formation of CH₂=C=CH₂ compound, only sp and sp² hybrid orbitals are involved,

i.e. sp² sp sp²
CH₂=C=CH₂

The general formula C_nH_2nO₂ could be for open chain carboxylic acid. For example, ethanoic acid C₂H₄O₂.

The +I effect is observed when a less electronegative atom or group is attached to the carbon chain. The alkyl groups are usually considered electron releasing or electron donating groups and push electrons towards the chain. Thus, (CH₃)₂CH- shows +I effect due to the presence of electron releasing group -CH₃.

The formula C₉H₁₂ can represent 8 isomeric hydrocarbons; three trimethyl benzene, three ethyl methyl benzene, one n-propyl benzene and one iso propyl benzene. This gives the correct number of isomers.

The compounds having same molecular formula but different number of carbon atoms (or alkyl groups) on either side of the functional group, are called metamers and this phenomenon is called metamerism. Metamerism is exhibited by the compounds having a bi-functional group i.e., -O-, -S-, -NH-, -CO- etc.