- 1). Write down the chemical reaction equation that the titration is based on. In our example, it is a reaction of the neutralization expressed as HCl + NaOH = NaCl + H2O.
- 2). Multiply the volume of the standard solution by its concentration to determine the number of moles of the titrant used for titration.
Number of moles = volume (in L) x molar (mole/L) concentration.
In our example, the volume of the NaOH solution used is 22.4 ml or 0.0224 L. Hence,
Number of moles (NaOH) = 0.0224 L x 0.15 mole/L = 0.00336 moles. - 3). Determine the number of moles of the titrated compound using the equation in Step 1. In our example, according to that equation, 1 molecule of HCl reacts with 1 molecule of NaOH. Thus, 0.00336 moles of NaOH (Step 2) would interact with 0.00336 moles of HCl).
- 4). Divide the number of moles of the compound (Step 3) by the aliquot volume (in L) to calculate the unknown concentration.
Molar concentration (mole/L) = number of moles/Volume (L).
In our example, the aliquot is 10 ml or 0.01 L. Hence the concentration of HCl would be 0.00336 moles/0.01L = 0.336 mole/L = 0.336 M.
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