Question

10. Hydrogen peroxide (H2O2: M = 34 g mol-1) is a powerful oxidising agent that is used in concentrated solution in rocket fuel systems and in dilute solution as in hair bleach. An aqueous solution of H2O2 is 30 % by mass and has a density of 1.11 g cm-3. Express the concentration of the solution in terms of: (i) Molality​

Answer 1

Answer:

The molality of solution=12.605 m

Explanation:

We are given that

Molar mass of Hydrogen peroxide, M=34 g/mol

Density of solution, $\rho=1.11gcm^{-3}$

30% Means mass of solute (Hydrogen peroxide)=30 g

Mass of solvent =100-30=70 g

Total mass of solution, m=100 g

Number of moles of solute=$\frac{given\;mass}{molar\;mass}$

Using the formula

Number of moles of hydrogen peroxide=$\frac{30}{34}$

Now, molality of solution

$m=\frac{number\;of\;moles\;of\;solute}{mass\;of\;solvent}\times 1000$

$m=\frac{30}{70\times 34}\times 1000$

$m=12.605 m$

Hence, the molality of solution=12.605 m