Basic Principles of Organic Chemistry Flashcards for NEET — 21 cards

First 8 of 21 Basic Principles of Organic Chemistry flashcards

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1. Card 1 of 21

   Explain Hyperconjugation (No-bond resonance).

   Hint: More alpha-hydrogens = more hyperconjugation structures = greater stability.

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   Answer

   It is a permanent effect involving the delocalization of $\sigma$ electrons of a C-H bond of an alkyl group directly attached to an atom with an unshared p-orbital (carbocation, free radical) or a $\pi$ bond (alkene).

2. Card 2 of 21

   What is the Electromeric Effect (E effect)?

   Hint: Temporary shift of pi electrons on demand.

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   Answer

   It is a TEMPORARY effect observed in multiple bonds (C=C, C=O) only in the presence of an attacking reagent. It involves the complete transfer of a shared pair of $\pi$-electrons to one of the atoms.

3. Card 3 of 21

   State Markovnikov's Rule for addition reactions.

   Hint: "The rich get richer" - Carbon with more hydrogens gets the hydrogen.

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   Answer

   When an unsymmetrical reagent (like HX) adds to an unsymmetrical alkene, the negative part of the reagent attaches to the double-bonded carbon that has FEWER hydrogen atoms.

4. Card 4 of 21

   What are the shapes and bond angles associated with $sp^3$, $sp^2$, and $sp$ hybridized carbon atoms?

   Hint: Think of methane, ethene, and ethyne.

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   Answer

   $sp^3$: Tetrahedral ($109.5^\circ$) $sp^2$: Trigonal planar ($120^\circ$) $sp$: Linear ($180^\circ$)

5. Card 5 of 21

   How do you calculate the number of sigma ($\sigma$) and pi ($\pi$) bonds in an organic molecule?

   Hint: Multiple bonds always contain exactly one sigma bond.

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   Answer

   Every single bond is 1 $\sigma$ bond. Every double bond has 1 $\sigma$ and 1 $\pi$ bond. Every triple bond has 1 $\sigma$ and 2 $\pi$ bonds.

6. Card 6 of 21

   What is the decreasing order of priority for principal functional groups in IUPAC nomenclature?

   Hint: Acids first, then derivatives, then aldehydes/ketones, alcohols, amines.

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   Answer

   $-\text{COOH} > -\text{SO}_3\text{H} > -\text{COOR} > -\text{COCl} > -\text{CONH}_2 > -\text{CN} > -\text{CHO} > >\text{C=O} > -\text{OH} > -\text{NH}_2 > >\text{C=C}< > -\text{C}\equiv\text{C}-$

7. Card 7 of 21

   What is metamerism? Give an example.

   Hint: Same formula, different chains around the central heteroatom.

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   Answer

   A type of structural isomerism due to unequal distribution of alkyl chains on either side of a polyvalent functional group (like $-O-, -S-, -NH-$). Example: Diethyl ether and Methyl propyl ether.

8. Card 8 of 21

   Explain keto-enol tautomerism. Which form is generally more stable?

   Hint: Shifting of an alpha-hydrogen and a double bond.

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   Answer

   It is a dynamic equilibrium between a ketone/aldehyde (keto form) and an alcohol attached to a double bond (enol form). The keto form is usually more stable due to the high bond energy of the C=O bond.