Question

A sample of NaOH weighing 0.38g is dissolved in water the solution is made to 50ml in volumetric flask. What is the molarity of the resulting solution?

Answer 1

no. of moles=given mass / molar mass
molar mass of NaOH= 23+16+1=40g
given mass=0.38g
no. of moles=0.38/40=9.5×10^-3
molarity=no. of moles/ volume in lit.
volume =50ml
molarity = 9.5×10^-3×10^3/50=1.9×10^-1

Answer 2

Answer:

0.19 mol/ L is the molarity of the resulting solution.

Explanation:

Mass of sodium = 0.38 g

Volume of the solution = 50 mL= 0.050 L

$Molarity=\frac{\text{Mass of NaOH}}{\text{Molar mass of NaOH}\times \text{Volume of solution(L)}}$

$M=\frac{0.38 g}{40 g/mol\times 0.050 L}=0.19 mol/l$

0.19 mol/ L is the molarity of the resulting solution.