In the anion ${\mathrm{HCOO}}^{-}$, the two carbon-oxygen bonds are found to be of equal length. What is the reason for this?

(a) $\mathrm{H}-\stackrel{+}{\mathrm{C}}=\stackrel{..}{\mathrm{O}}:\leftrightarrow \mathrm{H}-\mathrm{C}\equiv \stackrel{+}{\mathrm{O}}:$

(b) $\stackrel{-}{\mathrm{C}}{\mathrm{H}}_2-\stackrel{+}{\mathrm{N}}\equiv \stackrel{..}{\mathrm{N}}\leftrightarrow {\mathrm{CH}}_2=\stackrel{+}{\mathrm{N}}=\stackrel{-}{\mathrm{N}}$

(c) ${\mathrm{CH}}_3-\stackrel{+}{\mathrm{C}}\mathrm{H}-\underset{..}{\overset{..}{\mathrm{O}}}\mathrm{H}\leftrightarrow {\mathrm{CH}}_3-\mathrm{CH}=\underset{..}{\overset{+}{\mathrm{O}}}\mathrm{H}$

In which of the above pairs of resonance contributors, the structure on the right is an important contributor?

A 

B 

C 

D 

Correct order of stability of above alkenes is?

Which one of the following alkene(s) will react faster with ${\mathrm{H}}_2$ under catalytic conditions?

$-{\mathrm{CH}}_3$ group has $+\mathrm{IE}$. The influence of $+\mathrm{IE}$ increases with increase in $-{\mathrm{CH}}_3$ groups ($\mathrm{IE}$ = Inductive Effect).

(i)  

(ii)  

(iii)  

Correct order of stability of the above alkenes is