Question

The density of water is $1$ g/ml. The number of molecules present in 1 litre of water is:

• A. $18\times 6.023\times {10}^{23}$
• B. $1.8\times 6.023\times {10}^{23}$
• C. $6.023\times {10}^{23}$
• D. $55.55\times 6.023\times {10}^{23}$

Answer 1

The correct option is D $55.55\times 6.023\times {10}^{23}$

$1$ g$\to$ $1$ ml of water

$\therefore 1000$g $\to$ $1$ L of solution.

No. of moles $=\frac{1000}{18}=55.55$ moles

So, number of molecules $=$ No. of moles $\times 6.023\times {10}^{23}$

$=55.55\times 6.023\times {10}^{23}$

Hence, option D is correct.