Question

The total number of neutrons present in 54 mL $H_{2}O\left(l\right)$ are:

• A. $3N_A$
• B. $30N_A$
• C. $24N_A$
• D. none of these

Answer 1

The correct option is C $24N_A$

Molecular weight of $H_{2}O=18g$

No. of neutrons in $1$ mole i.e. $18g$ of $H_{2}O=8N_A$ ( from $O$ atom, as $H$ has no neutron)

Given moles of $H_{2}O=\frac{54}{18}=3$

$\therefore$ Total no. of neutrons present $=3\times 8N_A=24N_A$