Question

The density of ethanol is 60 y weight is 0.8937 g/ml what is the molarity

Answer 1

Step 1: Given data:-

Density of solution = $0.8937g/ml$
Weight percentage of ethanol = $60.00\%$
Molar mass of ethanol = $46.07gm/mole$

Step 2: Representing molarity:-

The weight percentage or $\%\mathrm{w}/\mathrm{w}$ represents the weight ratio of the solute and the solution.
And Molarity is represented as = $\frac{\mathrm{Moles}\mathrm{of}\mathrm{solute}}{\mathrm{Volume}\mathrm{of}\mathrm{solution}}$

Step 3: Formula for the weight percentage
$\%\mathrm{w}/\mathrm{w}=\frac{\mathrm{mass}\mathrm{of}\mathrm{solute}}{\mathrm{mass}\mathrm{of}\mathrm{solution}}\times 100$

Step 4: Calculation of molarity

Putting the values in the formula we get, $\mathrm{M}=\left(\frac{\%\mathrm{w}}{\mathrm{w}}\right)\times \mathrm{d}\times 10/\mathrm{Molecular}\mathrm{weight}$
$M=60\times 0.8937\times 10/46.07$
Molarity,$\mathrm{M}=11.63\mathrm{mol}/\mathrm{L}$

Thus, the molarity of ethanol is $11.63\mathrm{mol}/\mathrm{l}$.