Question

Locate pka stoichiometric points equivslence and explain relationship between volume naoh and ph weak acid

Aav Do = + 3 2 1 AaBbCcDdEe Normal OvA E a Figure 1-pH vs.Volume of NaOH with Bugatti Part A Trial 1 15 V NaOH (ML) tes) Focus D

Answer 1

When a weak acid is titrated with a strong base (NaOH) then first the pH is low which very slowly increases as shown in the graph because the weak acid do not dissociate completely to give respective ions, thus the so added NaOH forms highly ionised sodium salt which is responsible for the slow increase in the conductance of the solution. As a result the pH of solution begin to increase slowly as the acid is being consumed to neutralise the base.

But when the weak acid is completely neutralised further addition of strong base NaOH (which is capable of undergoing complete dissociation) will result in a sudden rise in the conductance of solution thereby rising the pH, this is mainly due to the increase in the concentration of free and fast moving OH^- ions which means the overall pH of the solution increases (i.e., solution is basic now) as the hydroxyl ion is free in the solution.

Thus the equivalence point in the above graph is 20 ml of NaOH from where the conductance and pH has shoot up.