What are the three States of matter? 

 Which of the following isn’t a Brønsted base?

 (a) PF5 

(b) H2O

 (c) NH3 

(d) S2-

 (e) CN-
 

 How would you increase the buffering capacity of a buffer made by adding NaHCO2 to an aqueous solution of HCO2H?

         (a) increase the concentration of HCO2H.

         (b) increase the concentration of NaHCO2.

          (c) increase the concentrations of both HCO2H and NaHCO2.

         (d) increase the ratio of the concentration of HCO2H to NaHCO2.

         (e) increase the ratio of the concentration of NaHCO2 to HCO2H.

Which of the following would have the strongest conjugate base?

  (a) H2O

 (b) H2S

 (c) NH3

 (d) PH3 (e) CH4
 

Which of the following negative ions would be the strongest base?

         (a) Cl2CHCO2-  (Cl2CHCOC2H: Ka = 7.8 x 10-3)

         (b) ClCH2CO2-   (ClCH2CO2H: Ka = 1.4 x 10-3)

         (c) HCO2-  (HCO2H: Ka = 1.8 x 10-4)

          (d) CH3CO2- (CH3CO2H: Ka = 1.8 x 10-5)
 

NaHCO3 can be used to neutralize strong bases, such as NaOH. What conclusion can be drawn from the fact that the following acid-base reaction proceeds to the right as written?

                    HCO3-(aq) + OH-(aq) ➝ CO32-(aq) + H2O(l)

          (a) HCO3- is a stronger acid than H2O

         (b) HCO3- is a stronger base than CO32-

         (c) HCO3- is a stronger base than OH-

         (d) CO32- is a stronger base than OH-

         (e) H2O is a stronger acid than HCO3-

 What is the value of Kb for the formate ion if Ka for formic acid is 1.8 x 10-4?

(a) Kb = Kw x Ka        (b) Kb = Ka/Kw          (c) Kb = Kw/Ka

(d) Kb = Kw + Ka            (e) Kb = Kw - Ka

The value of the equilibrium constant, Ka for the dissociation of formic acid in water,

HCO2H(aq) + H2O(l) ⇌ HCO2-(aq) + H3O+(aq)

would depend on:

 (a) the temperature 

(b) the pressure 

(c) the pH

 (d) the concentration of HOAc

  (e) the concentration of the OAc- ion.

Ammonia and the ammonium ion form a conjugate acid-base pair.

         NH3(aq) + H2O(l) ⇌ NH4+(aq) + OH-(aq)

Calculate the pH of 0.10 M NH3 if Ka for the NH4+ ion is 5.6 x 10-10

 (a) 4.7 

(b) 5.1

 (c) 5.7 

(d) 8.9

 (e) 11.1
 

 When NH4Cl is added to an 0.10 M NH3 solution, the pH of this solution:

(a) increases 

(b) decreases

 (c) remains the same

  (d) increases at first and then decreases.

     (e) decreases at first and then increases.