Question

Total number of electrons present in 18 ml of water: (density of water is 1 g mL${}^{-1}$)

• A. $6.02\times {10}^{23}$
• B. $6.02\times {10}^{22}$
• C. $6.02\times {10}^{24}$
• D. $6.02\times {10}^{25}$

Answer 1

The correct option is C $6.02\times {10}^{24}$

Density of water (given)$=1ℊ/㎖$

$\therefore 18㎖$ of water$=18ℊ$ of water

Molecular mass of wwater$=18ℊ/㏖$

$1$ molecule of $H_{2}O$ contains $10$ electrons in total.

[$2$ electrons from $2H$ and $8$ electrons from O]

Total number of electrons$=$(No. of electrons in $1$ molecule) $\times$ (Total no. of molecules)

$=10\times$(Avogadro's number)

$\Rightarrow 6.02\times {10}^{24}$ electrons.

Hence, the correct option is $C$