Organic Chemistry Some Basic Principles and Techniques Test - 9

In IUPAC naming is different alkyl groups are present, they are written in alphabetical order. Ethyl will be first, followed by methyl. Di, tri, tetra prefixes are not included in alphabetical order.

If more than one functional groups are present in the chain, one will be the main functional group on priority basis and mentioned as a sec. suffix, while the others are written as prefix mentioned as oxo along with locant.

Electronegativity of carbon atom depends on its hybridized state and percentage of ‘s’ character. Electronegativity is directly proportional to percentage of ’s’character, \(sp^3\) (25% ‘s’ character) < \(sp^2\)(33% ‘s’ character) < sp(50% ‘s’ character). Carbon linked through two \(\pi\) bonds is sp hybridized.

Only in these two compounds all carbon atoms are in same hybridization state i.e., sp and \(sp ^2\) hybridized, respectively

The liquids are having sufficient difference in their boiling points. Liquids having different boiling points vaporize at different temperatures. The vapours are cooled and the liquids so formed are collected separately.

Functional isomers have same molecular formula but different functional group. Alcohols are functional isomers of ethers. Aldehydes are functional isomers of ketones. Cyanides are functional isomers of isocyanides. Only alkyl halides do not show functional isomerism.

This technique is applied to separate substances which are steam volatile and are immiscible with water. In steam distillation, steam, from a steam generator is passed through a heated flask containing the liquid to be distilled. The mixture of steam and the volatile organic compound is condensed and collected. The compound is later separated from water using a separating funnel.

Thin layer chromatography (TLC): It is a method for analyzing mixtures by separating the components of the mixture. TLC can be used to determine the number of components in the mixture, the identity of compounds and the purity of compounds by observing the appearance of a product or the disappearance of a reactant. It can also be used to monitor the progress of a reaction. TLC is a sensitive technique- microgram (0.000001)g quantities can be analyzed by TLC.

Partition chromatography is based on continuous differential partitioning of components of a mixture between stationary and mobile phases. Paper hromatography is a type of partition chromatography.

Electrophiles are +vely charged or electron deficient species. They are Lewis acids. \(AlCl_3\),\(SO_3\) are Lewis acids, \(NO^+_2\)\(CH^+_3\),\(CH_3\)-\(C^+\) = 0 are +vely charged species

In (I) case, +vely charged C is attached to two alkyl groups and +I effect stabilize carbocation.

In (II) case, +R effect of \(OCH_3\) group stabilize carbocation.

In (III) case, -I effect of -\(OCH_3\) gp. destabilizes carbocation.

In longest continuous chain both ethyl groups are included and \(3 ^{rd}\) and \(4 ^{th}\) carbon have methyl groups present as a substituent.

In position isomerism, two or more compounds differ in the position of substituent, functional group or multiple bonds but molecular formula is same. In pentanone-2 and pentanone-3, position of ketonic group is different.

\(CH_3-CH_2-CH_2-CO-CH_3\) and \(CH_3-CH_2-CO-CH_2-CH_3\)

When two or more compounds differ in the position of substituent atom or functional group on the carbon skeleton, they are called position isomers and this phenomenon is termed as position isomerism. Pent-2-ene and pent-l-ene are position isomers because differ in the position of double bond.