Titration (using phenolphthalein)

*** For those who have not noticed the previous comments about the accuracy in the video:
This video was made as a quick guide for one of my classes about what a titration is and it wasn’t meant to be an exact representation since that would have taken longer and I wanted to get to the end point faster so they could see what happens. I explained to them that it would need to be done more accurately if they were ever to do one themselves. ***
A titration experiment is used to calculate an unknown concentration of acid (or alkali) using a neutralisation reaction.

In this titration an alkali (with a known concentration) is carefully added to the acid (of unknown concentration) using a burette. The volume of alkali used in the experiment is needed in order to perform a calculation to work out the concentration of the acid.

The acid used in this titration is hydrochloric acid (HCl, 25ml volume, unknown concentration) and the alkali used is sodium hydroxide (NaOH, 0.1M concentration).

Useful equations to calculate the unknown concentration of acid:

number of moles = concentration x volume

concentration = number of moles ÷ volume

Concentration is measured in moles per litre (moldm-3)
Volume is measured in litres (decimetre cubed: dm3)

The equation for this reaction is:
hydrochloric acid + sodium hydroxide —- sodium chloride + water

HCl + NaOH —- NaCl + H2O
(using subscript for the 2 in H2O)


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  1. so when they finished the experiment, was the resulting solution alkali not acidic as it was pink? I thought that it was supposed to be neutral but the indicator says its alkali… I'm even more confused than when I started

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