Example solved problem
Calculate the volume in of 0.250 HCl required to react completely with 37.5 of 0.100 NaOH according to the equation given.
NaOH(aq)+ HCl(aq)
NaCl(aq) + H2O
n(NaOH) = 0.10 × 37.5 × 10–3
n(NaOH) = 3.75 × 10–3 mol
n(NaOH) = n(HCl) = 3.75 × 10–3 mol
V(HCl) = 0.0150 = 15.0
NaOH(aq)+ HCl(aq)
NaCl(aq) + H2OKnown | c(NaOH) V(NaOH) | n = c × V Step 1 | n(NaOH) |
Step 2 | n(HCl) |
Step 3 | V(HCl) | Unknown |
n(NaOH) = 0.10 × 37.5 × 10–3
n(NaOH) = 3.75 × 10–3 mol
Step 1: Use given information (concentration and volume) to calculate amount in moles of known substance
n(NaOH) = n(HCl) = 3.75 × 10–3 mol
Step 2: Calculate n(unknown) from n(known) and the coefficients on these substances in the balanced equation for the reaction.
| 0.250 | = | 3.75 × 10–3 mol |
| V(HCl) |
V(HCl) = 0.0150 = 15.0
Step 3: Use calculated n(unknown) and given c(unknown) to calculate V(unknown).