All courses › Chemistry 1 › Neutralisation

Neutralisation

A strong acid and a strong base neutralise each other mole for mole when both are monoprotic and monobasic, as hydrochloric acid and sodium hydroxide are. At the equivalence point the amount of base equals the amount of acid. The amount is concentration times volume. The volumes must have the same unit. The products are water and a salt. For hydrochloric acid and sodium hydroxide the salt is sodium chloride. The indicator changes colour when you are at the equivalence point.

csVs=cbVbc_s V_s = c_b V_bequivalence for a 1:1 reaction

Symbols

csc_sacid concentrationmol/L
VsV_sacid volumemL
cbc_bbase concentrationmol/L
VbV_bbase volumemL

Example

25 mL of hydrochloric acid at 0.20 mol/L is neutralised with 0.10 mol/L NaOH.

Vb=0.20⋅25/0.10=50V_b = 0.20 \cdot 25 / 0.10 = 50 mL.

If the acid is diprotic, twice as much monobasic base is needed. Check the reaction equation.
Practise acids, bases and pH for free →

← From pH to concentration · Oxidation number of sulfur →

Part of Chemistry 1: Acids, bases and pH.