Question

Give the order of the stabilities of the following:
i. a. $PhC{H}_2^{\oplus }$
b. $P{h}_{2}C\stackrel{\oplus }{H}$
c. $M{e}_{2}C{H}^{\oplus }$
d. $M{e}_3{C}^{\oplus }$
e. $C_2{H}_5^{\oplus }$
f. $C{H}_3^{\oplus }$
ii. a. $P{H}_3\dot{C}$
b. $Ph\dot{C}{H}_2$
c. $M{e}_3\dot{C}$
d. $\dot{C_2}{H}_5$
e. $\dot{C}{H}_3$
iii. a. (Ref. image)
b. $P{h}_3{C}^{\ominus }$
c. $M{e}_{2}C{H}^{\ominus }$
d. $\stackrel{\ominus }{C}{H}_3$
e. $\stackrel{\ominus }{C_2}{H}_5$
f. $M{e}_3{C}^{\ominus }$

• A. i. $b>d>a>c>e>f$
  ii. $b>a>c>d>e$
  iii. $a>b>e>c>d>f$
• B. i. $b>a>d>c>e>f$
  ii. $a>b>c>e>d$
  iii. $a>b>d>e>c>f$
• C. i. $b>a>c>f>d>e$
  ii. $a>b>e>c>d$
  iii. $a>b>e>c>d>f$
• D. i. $b>a>d>c>e>f$
  ii. $a>b>c>d>e$
  iii. $a>b>d>e>c>f$

Answer 1

The correct option is D i. $b>a>d>c>e>f$

ii. $a>b>c>d>e$
iii. $a>b>d>e>c>f$
i. The order of the stabilities is $P{h}_{2}C{H}^{\oplus }>PhC{H}_2^{\oplus }>M{e}_3{C}^{\oplus }>M{e}_{2}C{H}^{\oplus }>C_2{H}_5^{\oplus }>C{H}_3^{\oplus }$ (b > a > d > c > e > f)
More is the delocalization of positive charge by resonance with phenyl groups or hyperconjugtion with alkyl groups, more is the stability of the carbocation.
ii. The order of the stabilities is $P{h}_3\dot{C}>Ph\dot{C}{H}_2>M{e}_3\dot{C}>\dot{C_2}{H}_5>\dot{C}{H}_3$ (a > b > c > d > e)
More is the dlocalization of positive charge by resonanc with phenyl groups or hyperconjugtion with alkyl groups, more is the stability of the carbocation.
iii. The order of the stabilities is a > b > d > e > c > f
a.Aromatic (six electron systems with conjugation, resonance stabilised).
b. Triphenyl methane carbanion (stabilised by resonance by three $Ph$ groups).
d. $\stackrel{\ominus }{C}{H}_3$ ($1$ carbanion)
e. ${\stackrel{\ominus }{C}}_2{H}_5$ (ethtyl carbanion)
c. $2$ Carbanion
f. $3$ Carbanion (the stability of carbanion: $1>2>3$).