Use the References to access Important values if needed for this question. Be sure to specify states such as (aq) or (s). Use H30* for the hydronium ion. If a box is not needed leave it blank. If no reaction occurs leave all boxes blank and click on "submit". Write a net ionic equation for the reaction that occurs when aqueous solutions of perchloric acid and sodium hydroxide are combined. + +

why does the equilibrium concentration of H+(aq) increase as the concentration of a weak acid increases?

Q3. This question is about the pH of several solutions. Give all values of pH to 2 decimal places. (a) (i) Write an expression for pH. (b) (ii) Calculate the pH of the solution formed when 10.0 cm³ of 0.154 mol dm-³ hydrochloric acid are added to 990 cm³ of water. The acid dissociation constant, Ka, for the weak acid HX has the value 4.83 x 10-5 mol dm-³ at 25 °C. A solution of HX has a pH of 2.48 Calculate the concentration of HX in the solution. Page 4 of 14

Calculate K₂ or K from experimental data. The pH of a 0.14-M solution of chlorous acid (HCIO₂) is measured to be 1.49. Use this information to determine a value of Ka for chlorous acid. HCIO₂(aq) + H₂O(l)=CIO₂ (aq) + H₂O˚(aq) K₂ =