25 mL of 0.2 M HCl is exactly neutralized by 10 mL of NaOH solution. What is the concentration of the NaOH?
Answer and explanation
Correct answer: B. 0.5 M
- Step 1: HCl and NaOH react 1 : 1, so Ca Va = Cb Vb.
- Step 2: Cb = 0.2 x 25 / 10 = 0.5 M.
Answer
0.5 M.
Why not the others: At neutralization the moles of acid equal the moles of base; inverting the volumes or ignoring them gives the other values.
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