Question on: JAMB Chemistry - 2024

Here's how to solve this problem:

1. Write the balanced chemical equation:
   HCl + NaOH → NaCl + H₂O
   This equation shows that hydrochloric acid (HCl) reacts with sodium hydroxide (NaOH) in a 1:1 molar ratio.
2. Calculate the moles of NaOH:
   Moles of NaOH = Concentration × Volume
   Moles of NaOH = 0.20 mol/dm³ × 20 cm³
   Convert cm³ to dm³: 20 cm³ = 20 / 1000 = 0.02 dm³
   Moles of NaOH = 0.20 × 0.02 = 0.004 moles
3. Determine the moles of HCl required:
   Since the reaction is 1:1, 0.004 moles of HCl are required to neutralize 0.004 moles of NaOH.
4. Calculate the volume of HCl:
   Volume of HCl = Moles / Concentration
   Volume of HCl = 0.004 / 0.12 = 0.0333 dm³
5. Convert the volume to cm³:
   0.0333 dm³ × 1000 = 33.3 cm³

Therefore, 33.33 cm³ of 0.12 mol·dm^-3 HCl is required to neutralize 20 cm³ of 0.20 mol·dm^-3 NaOH.