Solution :
$$C{N^ - }$$ and $$CO$$ are isoelectronic because they have equal number of electrons.
In $$C{N^ - }$$ the number of electron $$ = 6 + 7 + 1 = 14$$
In $$CO$$ the number of electrons $$ = 6 + 8 = 14$$
Releted MCQ Question on Inorganic Chemistry >> Chemical Bonding and Molecular Structure
Releted Question 1
The compound which contains both ionic and covalent bonds is