25 mL of 0.25 mol/L HCl neutralises 40 mL of NaOH solution. What is the concentration of the NaOH?
Answer and explanation
Correct answer: A. 0.156 mol/L
- Step 1: The mole ratio HCl : NaOH is 1 : 1, so Ca Va = Cb Vb.
- Step 2: Cb = 0.25 x 25/40 = 0.156 mol/L.
Answer
0.156 mol/L.
Why not the others: 0.4 mol/L, 0.25 mol/L and 0.312 mol/L do not fit.
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