21.5- CHOICE OF INDICATORS FOR TITRATIONS Flashcards
What is the equivalence point? (volume)
volume at which exactly same number of moles of hydrogen ions has been added as there are moles of hydroxide ions
What is the end point?
volume of alkali or acid added when indicator just changes colour
Property that suitable indicator for particular titration needs to follow- colour change
colour change must be sharp rather than gradual at end point, that is, no more than one acid (or alkali) needed to give complete colour change. Indicator changes colour gradually over several cubic centimetres would be suitable + would not give sharp end point
Property that suitable indicator for particular titration needs to follow- end point
end point of titration given by indicator must be same as equivalence point, otherwise titration will give wrong answer
Property that suitable indicator for particular titration needs to follow- distinct colour change
indicator should give distinct colour change
What is the half-neutralisation point?
point half-way between the zero and the equivalence point
