Final answer:
A weak base is a compound that does not dissociate completely in water to produce hydroxide ions. Ammonia (NH3) is an example of a weak base that interacts with water to partially produce OH- ions, as are compounds like sodium hypochlorite and sodium carbonate. These compounds are common in household products and do not contain OH- ions in their formula.
Step-by-step explanation:
To determine which of the following compounds is a weak base, it's important to understand the concept of base ionization in solution. A strong base is a compound that is 100% ionized in solution. When the ionization is less than 100%, the compound is considered a weak base. Most strong bases contain the hydroxide ion, OH-, within their formula. Bases that do not contain OH- as part of their formula, such as ammonia (NH3), are typically weak bases because they do not dissociate completely in solution.
For example, ammonia is a weak base. When ammonia is dissolved in water, it reacts partially, as follows:
NH3(aq) + H2O(l) ← NH4+(aq) + OH-(aq).
While ammonia does not have hydroxide ions in its formula, it can still produce hydroxide ions (OH-) in water, but only partially, which is why it is classified as a weak base.
Other examples of weak bases include sodium hypochlorite (NaClO) in bleach, sodium carbonate (Na2CO3) and trisodium phosphate (Na3PO4) in laundry detergent, baking soda (sodium bicarbonate, NaHCO3) in toothpaste and baking powder, calcium carbonate (CaCO3) for use in lawns, and magnesium hydroxide (Mg(OH)2) and aluminum hydroxide (Al(OH)3) in antacids and laxatives. These compounds all react with water to some extent, producing OH- ions and thus displaying weak base properties.