Question

The number of water molecules in $1$ litre of water is:
A) $18$
B) $18 \times {10^3}$
C) ${N_A}$
D) $55.55{N_A}$

Answer 1

Water is known as the "universal solvent" on the grounds that it is equipped for dissolving a larger number of substances than some other fluid. This is critical to each living thing on earth. It implies that any place water goes, either through the air, the ground, or through our bodies, it brings significant synthetics, minerals, and supplements. In order to solve the question we need to know the molecular weight of water and number of moles present in it. A detailed discussion is shown below.

Complete step-by-step answer:
We know that the density of water$= 1gm - m{L^{ - 1}}$
Given volume of water $= 1L = 1000mL$
The mass of water will be $= volume \times density = 1000mL \times 1gm - m{L^{ - 1}} = 1000gm$
Molecular mass of water $= 18gm$
So, the number of moles present in $1$ litre of water will be $= \dfrac{{1000}}{{18}} = 55.55moles$
$1$Mol of water molecules contains ${N_A}$ molecules.
$55.55moles$Of water will contain $55.55{N_A}$molecules.

So, the number of water molecules present in $1$ litre of water will be $55.55{N_A}$

Note: The mole idea is a helpful technique for communicating the measure of a substance. When managing particles at a nuclear (or sub-atomic) level, even one gram of an unadulterated component is known to contain an immense number of molecules. This is the place where the mole idea is broadly utilized. It principally centers on the unit known as a 'mole', which is a tally of countless particles.