SAT Subject Test Chemistry




Acids, Bases, and Salts

Practice Exercises

1. The difference between HCl and HC2H3O2 as acids is

(A) the first has less hydrogen in solution

(B) the second has more ionized hydrogen

(C) the first is highly ionized

(D) the second is highly ionized

2. The hydronium ion is represented as

(A) H2O+

(B) H3O+

(C) HOH+

(D) H

3. H2SO4 is a strong acid because it is

(A) slightly ionized

(B) unstable

(C) an organic compound

(D) highly ionized

4. The common ionic reaction of an acid with a base involves ions of

(A) hydrogen and hydroxide

(B) sodium and chloride

(C) hydrogen and hydronium

(D) hydroxide and nitrate

5. Which pH is an acid solution?

(A) 3

(B) 7

(C) 9

(D) 10

6. The pH of a solution with a hydrogen ion concentration of 1 × 10−3 is

(A) +3

(B) -3

(C) ±3

(D) 1 + 3

7. According to the Brønsted-Lowry Theory, an acid is

(A) a proton donor

(B) a proton acceptor

(C) an electron donor

(D) an electron acceptor

8. A buffer solution

(A) changes pH rapidly with the addition of an acid

(B) does not change pH at all

(C) resists changes in pH

(D) changes pH only with the addition of a strong base

9. The point at which a titration is complete is called the

(A) end point

(B) equilibrium point

(C) calibrated point

(D) chemical point

10. If 10.mL of 1 M HCl was required to titrate a 20.mL NaOH solution of unknown concentration to its end point, what was the concentration of the NaOH?

(A) 0.5 M

(B) 1.5 M

(C) 2 M

(D) 2.5 M

Answers and Explanations

1. (C) The strength of an Arrhenius acid is determined by the degree of ionization of the hydrogens in the formula. The HCl ionizes to a great degree and is considered a strong acid, whereas HC2H3O2, acetic acid, which is found in vinegar, ionizes only to a small degree and is considered a weak acid.

2. (B) The hydronium ion is written as H3O+.

3. (D) H2SO4 is a strong acid because it is highly ionized.

4. (A) The basic reaction between an acid and a base is H+(aq) + OH(aq) → H2O() or H3O+(aq) + OH(aq) → 2H2O()

5. (A) The pH scale is 0 to 14; the numbers below 7 are acid and those above 7 are increasingly basic.

6. (A) Because the pH is defined as the negative of the log of the H+ concentration, it is -(log of 10−3), which is -(-3) or +3.

7. (A) By definition, a Brønsted-Lowry acid is a proton donor.

8. (C) A buffer solution resists the changes in pH.

9. (A) The point in a titration when the “unknown” solution has been neutralized—in the case of an acid/base titration—by the “standard” solution of known concentration is called the end point or equivalence point.

10. (A) Use the equation Macid × V2 = Mbase × Vbase and change mL to L by dividing by 1,000 mL/L to change 10. mL into .01 L and 20. mL into .02 L. Then substituting, you get 1 Macid × .01 Lacid = xMbase × .02 Lbase. Solving for x, you get x = 0.5 Mbase.