Example



Example

EXAMPLE  - Identification of Acids and Bases:

Identify (a) H2C2O4, (b) NaNO2, (c) H2SO4, (d) NaHCO3, (e) LiH2PO4, (f) potassium hydroxide, (g) sodium nitrate, (h) sulfurous acid, (i) hydrobromic acid, and (j) ammonia as either (1) an Arrhenius strong acid, (2) an Arrhenius weak acid, (3) an Arrhenius strong base, (4) an Arrhenius weak base, or (5) not acidic or basic in the Arrhenius sense (neutral).

Solution:

a. H2C2O4 is an acid because it has the form of an acid, HaXbOc. It is a weak acid because it is not on the list of strong acids: HCl(aq), HBr(aq), HI(aq), HNO3, HClO4, and H2SO4.

b. Sodium nitrite, NaNO2, is a base. Because it is an ionic compound, it contains an anion. Because the anion nitrite, NO2-, is not on the list of neutral or acidic anions, it is basic. The only common strong base anion is hydroxide, so compounds containing the nitrite ion must be weak bases.

c. Sulfuric acid, H2SO4, is on the list of strong acids.

d. Sodium hydrogen carbonate, NaHCO3, is a weak base. As an ionic compound, it contains an anion. The hydrogen carbonate ion, HCO3-, is not on the list of neutral or acidic anions.

e. Lithium dihydrogen phosphate, LiH2PO4, is a weak acid. The dihydrogen phosphate ion, H2PO4-, is on the list of acidic anions.

f. Ionic compounds that contain hydroxide, like potassium hydroxide, are strong bases.

g. Sodium nitrate, NaNO3, is not acidic or basic in the Arrhenius acid-base sense. As an ionic compound, it does contain an anion, but the nitrate ion is on the list of neutral anions.

h. Sulfurous acid, H2 SO3, is not on the list of strong acids, so it is a weak acid.

i. We know that hydrobromic acid, HBr(aq), is an acid because its name ends in acid, and its formula has the form of a binary acid. It is found on the list of strong acids.

j. Ammonia, NH3, is our one example of an uncharged weak base.

Click here to see a sample study sheet for this task.

Click here to see an exercise.

Click here to identify a series of formulas as representing weak acids, strong acids, weak bases, strong bases, or substances that are neutral in the Arrhenius acid/base sense. (Requires the Java Plug-in.)

Return to the Acid/Base Page.


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