Reference no: EM132582559
1)Methyl red is a commonly used acid-base indicator. The colour change for methyl red occurs between pH 4.6 (red) and pH 6.0 (yellow). If this indicator is added to a solution and the colour is yellow, which of the following statements about the solution is true?
a)The solution is acidic.
b)The pH is between 4.6 and 6.0.
c)The pH is greater than 6.0.
d)The solution is basic.
2)Which pair of aqueous 1.0 mol/L solutions could be chosen to develop a buffer?
I NH4Cl(aq) and HCl(aq)
II HF(aq) and NaF(aq)
III NH4Cl(aq) and NH3(aq)
a)II and III only
b)II only
c)I only
d)None of the solutions will be a buffer
3)Calculate the pH of the following solutions.
a)a solution that contains 4.8 x 10-2 mol/L hydrochloric acid
b)an aqueous solution that is 5.82 x 10-3 mol/L sodium hydroxide
4)a)A solution has a pH of 3.89. What is the concentration of hydronium ion a.b x10 -c format.
b)A solution has a pH of 3.89. What is the concentration of hydroxide ion a.b x10 -cd format.
5)The active ingredient in AspirinTM is acetylsalicylic acid, HC9H7O4 (Ka = 2.75 x 10-5). To treat your headache after writing exams, you take two tablets dissolved in 250 mL of water. If each tablet contains 0.32 g acetylsalicylic acid, find the pH of the solution.
6)Hydrazine, N2H4, is a base in aqueous solution. A 0.20 mol/L solution of hydrazine in water has pH = 10.77. What is Kb for hydrazine?
7)The two acid ionization constants for oxalic acid, HOOCCOOH, are Ka1 = 5.6 x 10-2 and Ka2 = 1.5 x 10-4. What is the base dissociation constant, Kb, for OOCCOO2-(aq)? Express your answer in the a.b x 10-cd format.
8)Sodium azide, NaN3(s) has many uses. It is the chemical used to make automobile air bags inflate with N2(g), and it is sometimes added to water to kill bacteria. What is the pH of a 0.010 mol/L aqueous solution of NaN3(aq)? Only the azide ion, N3-(aq), affects the pH of water. For hydrazoic acid, HN3(aq), Ka = 1.9 x 10-5.