Which of the following chemical species are not related through resonance?

(a) ${\mathrm{CH}}_3{\mathrm{COCH}}_2{\mathrm{COOC}}_2{\mathrm{H}}_5 \text{and} {\mathrm{CH}}_3\left(\mathrm{OH}\right)={\mathrm{CHCOOC}}_2{\mathrm{H}}_5$

(b)  

(c)  

(d)  

What is the correct stability order of the following carbanions?

$\left(\mathrm{i}\right) {\mathrm{CH}}_3-\mathrm{CH}=\mathrm{CH}-\stackrel{\ominus }{\mathrm{C}}{\mathrm{H}}_2$

$\left(\mathrm{ii}\right) {\mathrm{CH}}_3-\mathrm{CH}=\mathrm{CH}-\stackrel{\ominus }{\mathrm{C}}({\mathrm{CH}}_3{)}_2$ 

$\left(\mathrm{iii}\right) {\mathrm{CH}}_3-\mathrm{CH}=\mathrm{CH}-\stackrel{\ominus }{\mathrm{C}}\mathrm{H}-{\mathrm{CH}}_3$

What is the order of stability of the following carbocations?

Which of the following intermediate sites have a similar geometry?

$\left(\mathrm{i}\right)$ $\stackrel{+}{\mathrm{C}}{\mathrm{H}}_2{\mathrm{CH}}_3$

$\left(\mathrm{ii}\right)$ $\stackrel{-}{\mathrm{C}}{\mathrm{H}}_2{\mathrm{CH}}_3$

$\left(\mathrm{iii}\right)$ $:\stackrel{-}{\mathrm{C}}{\mathrm{H}}_2{\mathrm{COCH}}_3$

$\left(\mathrm{iv}\right)$ ${\mathrm{CH}}_2=\mathrm{CH}-\stackrel{-}{\mathrm{C}}{\mathrm{H}}_2$

$\stackrel{\mathrm{A}}{\mathrm{C}}{\mathrm{H}}_3\stackrel{\mathrm{B}}{\mathrm{C}}\mathrm{H}=\mathrm{CH}-\stackrel{\mathrm{C}}{\mathrm{C}}{\mathrm{H}}_2-\stackrel{\mathrm{D}}{\mathrm{C}}{\mathrm{H}}_2-\stackrel{\mathrm{E}}{\mathrm{C}}\mathrm{H}{\left({\mathrm{CH}}_3\right)}_2$

The order of homolytic bond dissociation energy of different $\mathrm{C}-\mathrm{H}$ bonds is: