Question

The molarity of a solution obtained by mixing $800mL$ of $0.5M$ $HCl$ with $200mL$ of $1M$ $HCl$ will be:

• A. $0.8M$
• B. $0.6M$
• C. $0.4M$
• D. $0.2$M

Answer 1

The correct option is B $0.6M$

$M=\frac{(V_1\times M_1)+(V_2\times M_2)}{V_1+V_2}$

$M=\frac{(\text{800 mL}\times \text{0.5 mol/L})+(\text{200 mL}\times \text{1 mol/L})}{\text{800 mL}+\text{200 mL}}=\text{0.6 M}$

Hence, option B is correct.