Question

1) Describe what happens in an acid-base titration.

2) Human blood behaves as a buffer. Why would this be important? Provide two examples of how blood might react to a change in pH.

3) Use Le Chatelier's principle to explain how the common ion effect affects the pH of a weak acid solution.

Answer 1

Solution:- In an acid-base titration, we generally take acid in a conical flask and fill base in the burette also add few drops of the indicator in the acid then we start adding the base to acid till the indicator changes the color. So the chemistry behind this is that indicators change their color in different pH so initially, indicator is in acidic medium and when we start adding base, base will start neutralizing the acid and when the whole acid is neutralized the medium will become basic and in the basic medium indicator will change is color so we will be able to know that the endpoint has reached and we can stop adding further base. by this, we can find the concentration of the unknown acid.

2) pH of human blood =7.15 - 7.45 , this is regulated vis carbonate concentration in blood

If the pH of blood will be less than 7.15 it is called acidosis, in this our nervous system does not work properly and common symptoms are headache and problem in excretion. and when pH is above 7,45 it is called alkalosis in this muscular weakness is observed and transport proteins become more ionized which cause tetany.

3) Le chatelier's principle: it states that on changing the tempertature ,pressure and concentration of reactant and product the equilibrium gets disturbed on this change reaction either proceeds backward or forward to restore the change. so in weak acid solution if we add salt of its conjugate base the pH decreasses because of increasing the ion in product side.

HB --------- H⁺   + B^- so on increasing B^- reaction will move backward and pH will decrease.