Question

The number of lone pairs and bond pairs in hydrazine are respectively:

• A. 2 and 4
• B. 2 and 6
• C. 2 and 5
• D. 1 and 5

Answer 1

The correct option is C 2 and 5

Hydrazine has molecular formula $N_2{H}_4$ and its structure is determined as:

total number of valence electrons = $2\times 5+4\times 1=14e^{-}$

Place the most electro-negative atom ($N$ here) as central atom and other atoms around it joined by single bond each. Thus, 10 $e^{-}$ are used in bonding and remaining $14-10$=4 $e^{-}$ will go to cental $N$ to complete its octet.

Therefore from the hydrazine structure it has 5 bond pairs and 2 lone pairs of electron.

Option C is correct.