Dilution Problem - Mixed category

9. Altering Product Strength 9.1) Dilution 9.1.1) Dilution

9.1.1.1) Find initial concentration in dilution Challenging 1


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Calculate the quantity of solvent you need to add into 43 mL of a 37.75 % solution to prepare a 5.67 % solution?


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lb equals 243.5 mL kg

    This is a volume expansion or concentration dilution type problem. The essential formula is `Q_1C_1 = Q_2C_2`.
    Here,

    `Q_1` = initial quantity = `43\quadmL`.
    `C_1` = initial concentration = `37.75\quad%`
    `Q_2` = final quantity = `?\quad mL`.
    `C_2` = final concentration = `5.67\quad %`

    Therefore, rearranging the formula, we get:
    `Q_2 = (Q_1 × C_1)/(C_2)` `therefore Q_2 = (43 × 37.75) /5.67=286.5\quad mL` in nearest whole number.

    Now, subtract the initial quantity of the solution (`43\quadmL`) from this final quantity (`286.5\quadmL`) to determine the amount of solvent to be added: `286.5\quadmL-43\quadmL=243.5\quadmL`. (Ans)