If an acid has a ka=1.6x10^-10, what is the acidity of the solution?

The information given in the question is not enough to determine the acidity of the solution. This is because, acidity can only be found with the equation: pH = -log [H+].
 In order to determine the acidity of the solution, the half titration point value is needed, this will make it possible to determine the value of H30+.  If the half point titration value is known, then Ka will be equivalent to pH and the value will be evaluated using the equation: - log (1.6 * 10^-10).

1= c 2= a or d3 = idk sorry 4= c5= c