Question

To a 4 L of 0.2 M solution of NaOH, 2 L of 0.5 M NaOH are added. The molarity of resulting solution is

• A. 0.9 M
• B. 0.3 M
• C. 1.8 M
• D. 0.18 M

Hint:

$M_1V_1 + M_2V_2 = M_3(V_1+V_2)$.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
$M_1V_1 + M_2V_2 = M_3(V_1+V_2)$.
Step 2: Detailed Explanation:
Total moles = $4 \times 0.2 + 2 \times 0.5 = 0.8 + 1.0 = 1.8$ mol. Total volume = $4 + 2 = 6$ L. Molarity = $\frac{1.8}{6} = 0.3$ M.
Step 3: Final Answer:
The molarity is 0.3 M.