Carbocation and carbanion stability from structures

14 questions on Carbocation and carbanion stability from structures from the General Organic Chemistry I: Electronic Effects chapter: 3 NEET level, 5 JEE Main, 6 JEE Advanced. Each one opens with its answer and solution.

• Loss of a hydride ion from a C-H bond of the compound shown can give two different carbocations. The one formed preferentially is NEET level, drawn structure
• The carbon bearing the lone pair in the anion shown has high s-character, which makes the anion far more stable than an alkyl carbanion. What are its hybridisat... NEET level, drawn structure
• The ion shown is more stable than the n-propyl cation mainly because of NEET level, drawn structure
• The aromatic hydrocarbon shown can form the cations drawn after loss of hydride. Which cation shown is the most stable? JEE Main level, drawn structure
• A saturated bicyclic hydrocarbon is shown for reference. Which of the carbocations shown is the least stable? JEE Main level, drawn structure
• The hydrocarbon shown is for reference. Which of the carbanions shown is the most stable? JEE Main level, drawn structure
• The cation shown is much more stable than the ethyl cation even though oxygen is electronegative. This is because JEE Main level, drawn structure
• The compound shown is a carbon acid with pKa about 10, far lower than that of methane (about 50). The main reason is that its conjugate base is stabilised by JEE Main level, drawn structure
• The primary cation shown is the reference. Select all of the cations shown that are more stable than it. JEE Advanced level, drawn structure
• The cation shown undergoes a single 1,2-shift to give a more stable cation. Which structure is formed? JEE Advanced level, drawn structure
• The compound shown is treated with one equivalent of base. Which hydrogens are removed, and how many resonance structures (counting the carbanion form and enola... JEE Advanced level, drawn structure
• The alcohol shown ionises (loss of hydroxide) to give a carbocation. Counting each carbon atom separately, how many carbon atoms carry the positive charge in at... JEE Advanced level, drawn structure
• Select all correct statements about the anion shown. JEE Advanced level, drawn structure
• The parent cation is shown. Select all of the substituted cations shown that are LESS stable than the parent cation. JEE Advanced level, drawn structure