A 0.21 M solution of a weak acid HA dissociates such that 99.4% of the weak acid remains intact (i.e., remains as HA). To the nearest hundredths, what is the pH of the solution? Give clear handwritten Solution

Consider two weak acids, HA (MM=138g/mol)and HB (MM=72.0g/mol). A solution consisting of 11.0 g of HA in 745 mL has the same pH as a solution made up of 5.00 g of HB in 525 mL. Which of the two acids is stronger? Justify your answer by an appropriate calculation.

A solution is made by dissolving 15.0 g sodium hydroxide in approximately 450 mL water. The solution becomes quite warm, but after it is allowed to return to room temperature, water is added to bring the volume to 500.0 mL of solution. (a) Calculate the pH and pOH in the final solution. (b) Why would we wait for it to return to room temperature? (c) If the mass of the water used to initially dissolve the sodium hydroxide were exactly 450 g and the temperature of the water increased by 8.865 C, how much heat was given off by the dissolution of 15.0 g of solute? Assume the specific heat of the solution is 4.184 J/g. K. What is the molar heat change for the dissolution of sodium hydroxide (known as the enthalpy of solution, Hsol)?

Why have chemists not tabulated the fraction ionized for different acids? Such a table would make problems such as calculating the pH of an acid solution quite simple.

You have a solution of the weak acid HA and add some HCl to it. What are the major species in the solution? What do you need to know to calculate the pH of the solution, and how would you use this information? How does the pH of the solution of just the HA compare with that of the final mixture? Explain.

A 1000.-mL solution of hydrochloric acid has a pH of 1.3. Calculate the mass (g) of HCl dissolved in the solution.

. Using Fig. 16.3, list the approximate pH value of live “everyday” solutions. How do the familiar properties (such as the sour taste for acids) of these solutions correspond to their indicated pH?

Rank the compounds in each of the following groups in order of increasing acidity or basicity, as indicated, and explain the order you assign. (a) acidity: HCI, HBr, HI. (b)basicity: H2O, OH-, H-, CI-. (c) basicity: Mg(OH)2, Si(OH)4, ClO3(OH) (Hint: Formula could also be written as HCIO4). (d) acidity: HF, H2O, NH3, CH4

The sec-butyl cation can react as both a Brnsted-Lowry acid (a proton donor) and a Lewis acid (an electron pair acceptor) in the presence of a watersulfuric acid mixture. In each case, however, the product is different. The two reactions are as follows: (a) In which reaction(s) does this cation react as a Lewis acid? In which reaction(s) does it react as a Brnsted-Lowry acid? (b) Write Lewis structures for reactants and products and show by the use of curved arrows how each reaction occurs.

Benzoic acid (K a=6.6105)is present in many berries. Calculate the pH and % ionization of a 726-mL solution that contains 0.288 mol of benzoic acid.