Question

Find molarity of pure water where H2O = 18​

Answer 1

$\sf\large\underline\blue{Given:-}$

• Molar mass of Water is = 18 g/mol

$\sf\large\underline\blue{To\: Find :-}$

• What's the molality of pure water?

$\sf\large\underline\blue{Formula\: used:-}$

$\pink{\bigstar \ \boxed{\rm Molality= \dfrac{No. \ of \ moles\ of \ Water}{Weight \ of \ solvent \ (Kg)}}}$

Where,

Solvent = Water

$\sf\large\underline\blue{Solution:-}$

Given that,

Molar mass of Water is = 18 g/mol

We know that,

Density of Water = 1 Kg/L

Therefore, mass of water will be = 1 Kg

Or, 1000gm

Now, find number of moles of water

$\pink{\bigstar}$Number of moles of water

= 1000/18

= 55.55 moles

_____________________________________________________

$\pink{\bigstar}$Molarity

= 55.55/ 1 M

= 55.55 M

$\small{\underline{\sf{\blue{Hence-}}}}$

Molarity of pure water is = 55.55 M