Chloroacetic acid is a stronger acid than acetic acid. This can be explained using

Which one of the nitrogen atoms in $H_2N-NH-CO-NH_2$ (where the atoms are labeled $I, II, III$ as shown in the structure) is the most nucleophilic?

The $+I$ effect of alkyl groups is in the order:

Identify the most stable species in the following set of ions giving reasons.
$(a) \ \stackrel{+}{C} H_{3}, \stackrel{+}{C} H_{2} Br, \stackrel{+}{C} HBr_{2}, \stackrel{+}{C} Br_{3}$
$(b) \ \stackrel{\Theta}{C} H_{3}, \stackrel{\Theta}{C} H_{2} Cl, \stackrel{\Theta}{C} HCl_{2}, \stackrel{\Theta}{C} Cl_{3}$

Which of the following is the most stable carbanion?

Which of the following $\sigma$-bonds participate in hyperconjugation?