Question

how do the structure and the initial concentration of an acid and a base influence pH of the resultant soluttion during a titration

Answer 1

Suppose we have an acid which is very stable in its conjugate base form, the pH of such an acid would be low (large H+ concentration) and loosing a proton is favorable in the reaction. If we have an acid which has relatively unsatable or less stable conjugate base form then neutral acid form, the forward reaction is less prone and acidity would thus be low, that is pH of it would be high (low H+ concentration). Similarly for base If conjugate acid form is more stable the pH would be high, that is more basic (low H+ concentration).

Concentration plays a major role, Dissociation of acids are known to be higher in low concentration solutions of acids or base as opposed to a very concentrated solution.