25.0 cm3 of sodium hydroxide solution is neutralised by 20.0 cm3 of 0.100 mol dm-3 hydrochloric acid. What is the concentration of the sodium hydroxide?
Answer and explanation
Correct answer: C. 0.0800 mol dm-3
- Step 1: Moles of HCl . Step 2. NaOH + HCl is 1:1, so moles NaOH . Step 3. Concentration . Answer: 0.0800 mol dm-3. Why not the others: 0.125 inverts the volumes; 0.0500 divides by 40.0 cm3; 0.800 misplaces the decimal.
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