Correct option is C)
Density of water (d)=1g/ml
Mass of 1ml of water= 1g
Number of molecules in 1gm of water=
18
1×6.022×10
23
Volume of
18
6.023×10
23
molecules= 1ml
∴ Volume of 1 molecule=
18
6.023×10
23
1
=3×10
−23
ml
Hence, the correct option is C