Question

$10\, mL$ of $2(M)$ $NaOH$ solution is added to $200\, mL$ of $0.5 (M)$ of $NaOH$ solution. What is the final concentration ?

• A. 0.57 (M)
• B. 5.7 (M)
• C. 11.4 (M)
• D. 1.14 (M)

Answer 1

Answer: (A)

0.57 (M)

Answer 2

From molarity equation
$M_{1} V_{1}+M_{2} V_{2} =MV_{\left(total\right)}$
$2\times\frac{10}{1000}+0.5\times\frac{200}{1000}=M \times\frac{210}{1000}$
$120=M \times210$
$M=\frac{120}{210}=0.57 M$