Solution

Moles of NaOH in 1 g $= \frac{1}{40} = 0.025$ mol Moles of HCl in 25 mL $= \frac{0.75 \times 25}{1000} = 0.01875$ mol NaOH and HCl react 1 : 1, so moles of NaOH unreacted $= 0.025 - 0.01875 = 0.00625$ mol Mass of NaOH unreacted $= 0.00625 \times 40 = 0.25$ g $= 250$ mg

Concept Limiting reagent calculation in neutralisation

Some Basic Concepts of Chemistry in past papers

49 questions from this chapter have appeared across 23 exam years.