Question

What quantity (in mL) of a $45$% acid solution of a mono-protic strong add must be mixed with a $20$% solution of the same acid to produce $800mL$ of a $29.875$% acid solution?

• A. $316$
• B. $330$
• C. $320$
• D. $325$

Answer 1

Answer: (A)

$316$

Let $x$ mL of a 45% acid solution of a monoprotic strong add must be mixed with a $20\%$ solution of the same acid to produce 800 mL of a $29.875\%$ acid solution.
$C_1{V}_1+C_2{V}_2=C_3{V}_3$

Here, $C_1,C_{2}and{C}_3$ are concentrations and $V_1{V}_{2}and{V}_3$ are volumes.

$45x+20(800-x)=29.875\left(800\right)$

$x=316$ mL

Hence, 316 mL of a $45\%$ acid solution of a mono-protic strong add must be mixed with a $20\%$ solution of the same acid to produce 800 mL of a $29.875\%$ acid solution.