BACK TITRATION

This video introduces the concept of back titration. Back titration involves reacting a substance of unknown concentration with an excess acid of known concentration. The acid in excess is then reacted with a base in another reaction. The base is of known concentration and its moles that reacted is determined using the volume determined using titration. The mole ratios are then used to determine the moles of the acid that react in the second reaction, these number of moles are then used to determine the volume of the acid using the concentration. The volume is then subtracted from the initial volume before the reaction to determine the volume that reacted in the first reaction. The volume is then used to determine the moles of the acid that reacted in the first reaction, mole ratios are used finally to determine moles of the unknown substance of known volume. Having moles and volume we can then calculate the concentration.