13) In which of the following aqueous solutions does the weak acid e xhibit the lowest
percentage ionization?
A) 0.01 M HCN (Ka = 6.2 x 10-10)
B) 0.01 M H2CO3 (Ka = 4.5 x 10-7)
C) 0.01 M HNO2 (Ka = 4.0 x 10-4)
D) 0.01 M HCHO2 (Ka = 1.8 x 10-4)
E) 0.01 M HOCl (Ka = 3.5 x 10-8)
14) Calculate the pH of a solution prepared by dissolving 0.250 mol of benzoic acid
(C7H5O2H) and 0.150 mol of sodium benzoate (NaC7H5O2) in water sufficient to yield
1.00 L of solution. The Ka of benzoic acid is 6.50 x 10-5.
A) 4.409
B) 3.965
C) 10.035
D) 9.591
E) 5.190
15) When the following equation is balanced, the coefficients are ________.
NH3 (g) + O2 (g) → NO2 (g) + H2O (g)
A) 1, 1, 1, 1
B) 4, 7, 4, 6
C) 2, 3, 2, 3
D) 1, 3, 1, 2
E) 4, 3, 4, 3
16) Nonmetals can be ________ at room temperature.
A) solid, liquid, or gas
B) solid or liquid
C) solid only
D) liquid only
E) liquid or gas