Final answer:
The concentration of the sodium hydroxide solution neutralized by hydrogen bromide was 0.375 M, calculated using the volumes and molarities given for the titration and realizing the molar ratio of 1:1 between NaOH and HBr.
Step-by-step explanation:
To find the concentration of sodium hydroxide (NaOH) that was neutralized by hydrogen bromide (HBr), we first need to write down the balanced chemical equation for the reaction:
NaOH (aq) + HBr (aq) → NaBr (aq) + H₂O (l)
From the equation, we see that the molar ratio is 1:1 between NaOH and HBr. To find the moles of HBr that reacted, we use its concentration and volume:
Moles of HBr = molarity (M) × volume (L)
= 0.250 M × 0.030 L
= 0.0075 moles
Since the molar ratio between HBr and NaOH is 1:1, moles of NaOH will also be 0.0075. Now, we can find out the concentration of NaOH using its volume and the number of moles:
Concentration of NaOH = Moles of NaOH / Volume of NaOH (L)
= 0.0075 moles / 0.020 L
= 0.375 M
Therefore, the concentration of the sodium hydroxide solution was 0.375 M.