Solution :
lt is given that in 18 mL of water their are [tex]6.022\times 10^{23}[/tex] water molecules.
We know, that 1 molecule of water contains 2 atoms of hydrogen.
Hydrogen atom in 18 mL water is,
[tex]2\times 6.022\times 10^{23} = 12.044 \times 10^{23}[/tex] .
So, number of hydrogen atoms in 1 L = 1000 mL are :
[tex]N = \dfrac{1000}{18}\times 12.044\times 10^{23}\\\\N = 6.69 \times 10^{25}\ atoms[/tex]
Hence, this is the required solution.
