What are the characteristics of the inductive effect?

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

Given below are two statements:
Statement $I$: On the basis of inductive effect, the order of stability of alkyl carbanions is $CH_3^- > CH_3CH_2^- > (CH_3)_2CH^- > (CH_3)_3C^-$.
Statement $II$: Allyl and benzyl carbanions are more stabilised by inductive effect and not by resonance effect.

The arrangement of $CH_3-CH_2-CH_2-$,$(CH_3)_2CH-$,and $(CH_3)_3C-$ groups in increasing order of their inductive effect ($+I$ effect) is:

The electromeric effect in organic compounds is a....

The structure of triphenylmethyl cation is given below. This is very stable and some of its salts can be stored for months. Explain the cause of high stability of this cation.