Question

a solution of NaoH conatins 30gms of this compound in 1.5dm^3 of solution. What is the molarity of the solution??

Answer 1

The solution of NAOH contains 30 gms of this compound in 1.5 dm3 of solution. What is the molarity of this solution?

The chemical formula is NaOH, not NAOH. This matters in Chemistry.

molarity (M) = moles of solute/liters of solution = mol/L (1 L = 1 dm³)

First calculate moles of NaOH in 30 g.

n = m/M; where n = moles, m = mass (g), and M = molar mass (g/mol).

m(NaOH) = 30 g NaOH

M(NaOH) = 23 g/mol Na + 16 g/mol O + 1 g/mol H = 40 g NaOH/mol NaOH

n(NaOH) = 30 g NaOH/40 g NaOH/mol NaOH = 0.75 mol NaOH

Calculate the molarity of NaOH solution.

molarity = 0.75 mol NaOH/1.5 L = 0.50 mol NaOH/L = 0.50 mol NaOH/dm³ = 0.50 M NaOH

Answer 2

Answer:

Given,

Mass of NaOH = 30gms

We know,

Molecular weight of NaOH = 40 g

No. of moles = Mass/ Molecular weight

= 30/40

= 0.75 mol

Volume of solution = 1.5dm^3

Now,

Molarity = No. of moles/Volume

= 0.75/1.5

= 75/150

= 1/2 = 0.5M