Question

a sample of NaOH WEIGHING 0.40 gram is dissolved in water and the solution is made to 50 centimetre cube in volumetric flask what is the molarity of resulting solution​

Answer 1

Hey Friend!

Answer:

0.2 M

Explanation:

$Given,\\\\\star \ Weight\ of\ NaOH = 0.40 \ g\\ \star \ Volume\ of \ the \ solution = 50 \ cm^3\\\\To \ find\ Molarity \\\\Now,\\Molar \ mass\ of\ NaOH = 23 + 16 + 1 = 40 \ g/mol \\\\Hence,\\number \ of\ moles\ in\ 0.40 \ g \ of\ NaOH = \frac{grams\ of \ NaOH}{molar\ mass}\\ \\= \frac{0.4}{40} = 0.01 \ mol\\ \\We \ know\ that\\\\Molality = \frac{no. \ of \ moles \ of \ solute}{volume\ of\ solution\ ( in\ l)} \\\\\\= \frac{1 \ * \ 1000}{50 \ * \ 100} \\\\ = \frac{1}{5}\\ \\= 0.2$

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