Question

Label each of the following statements as true or false. Explain your answers, and provide an example for each that supports your answer. a. All nonelectrolytes are insoluble. b. All insoluble substances are nonelectrolytes. c. All strong electrolytes are soluble. d. All soluble substances are strong electrolytes.

Short answer

a. False. Some nonelectrolytes are soluble, like ethanol (\(C_2H_5OH\)). b. True. Insoluble substances like silver chloride (\(AgCl\)) are nonelectrolytes because they don't dissolve or ionize in water. c. True. Strong electrolytes, like sodium chloride (\(NaCl\)), must be soluble to ionize completely in water. d. False. Soluble substances can be weak electrolytes or nonelectrolytes, like acetic acid (\(CH_3COOH\)), which ionizes only partially.

Step-by-step solution

Statement a: All nonelectrolytes are insoluble

This statement is false. A nonelectrolyte is a substance that does not ionize when dissolved in water and thus doesn't conduct electricity. It's not necessary for a nonelectrolyte to be insoluble; some nonelectrolytes are soluble. Example: Ethanol (\(C_2H_5OH\)) is a nonelectrolyte but is soluble in water.

Statement b: All insoluble substances are nonelectrolytes

This statement is true. An insoluble substance is one that does not dissolve in water. Since it does not dissolve, it cannot form ions in water and therefore cannot be an electrolyte. Example: Silver chloride (\(AgCl\)) is an insoluble substance which does not dissolve or ionize in water, making it a nonelectrolyte.

Statement c: All strong electrolytes are soluble

This statement is true. A strong electrolyte is a substance that completely ionizes when dissolved in water, resulting in a solution that conducts electricity. A strong electrolyte needs to be soluble in order to ionize. Example: Sodium chloride (\(NaCl\)) is a strong electrolyte and is soluble in water, forming sodium (\(Na^+\)) and chloride (\(Cl^-\)) ions.

Statement d: All soluble substances are strong electrolytes

This statement is false. A soluble substance dissolves in water but does not necessarily ionize completely or even partially. A soluble substance can be a weak electrolyte or a nonelectrolyte. Example: Acetic acid (\(CH_3COOH\)) is soluble in water, but it's a weak electrolyte, as it ionizes only partially when dissolved in water.

Key concepts

Nonelectrolytes

A common stumbling block in understanding chemical solutions lies in the classification of substances when they are dissolved. Nonelectrolytes represent a category of substances that do not dissociate into ions when dissolved in water. This means that, despite being in a solution, they remain as whole molecules and do not produce charges that can conduct electricity.

However, the confusion often arises with the notion that nonelectrolytes are insoluble. This is a misconception; many nonelectrolytes are quite soluble. For example, table sugar or sucrose (\(C_{12}H_{22}O_{11}\)) dissolves in water but does not split into ions; it remains non-ionic and thus does not facilitate electrical conductivity. This clearly demonstrates that solubility is not synonymous with electrolyte strength.

Strong Electrolytes

When discussing strong electrolytes, we are referring to substances that disassociate completely into ions in an aqueous solution. This complete ionization is key to their ability to conduct electricity very well.

Examples of strong electrolytes include most salts, such as sodium chloride (\(NaCl\)), as well as strong acids like hydrochloric acid (\(HCl\)) and strong bases like sodium hydroxide (\(NaOH\)). It's a common error to believe that all soluble substances are strong electrolytes. The truth is, while all strong electrolytes are soluble, not all soluble substances are strong electrolytes, which can be weak electrolytes or nonelectrolytes. Solubility merely implies that a substance can dissolve in a solvent but does not comment on its electrical conductivity.

Solubility in Chemistry

In chemistry, solubility is a property referring to the maximum amount of a solute that can dissolve in a solvent at a specific temperature and pressure to form a homogeneous solution. The solubility of a substance in water can be greatly affected by temperature and the presence of other chemicals.

The misunderstanding that solubility equates to being an electrolyte is common, but it is important to distinguish the two. Some highly soluble substances do not break down into ions and are classified as nonelectrolytes while others only partially ionize, termed weak electrolytes. Conversely, some compounds like calcium carbonate (\(CaCO_3\)) have low solubility in water but are considered to be weak electrolytes because they do partially ionize.

Conductivity in Solutions

When it comes to conductivity in solutions, it all hinges on the presence of free-flowing, charged particles, or ions. A solution's ability to conduct an electric current directly depends on the concentration of these ions.

Conductivity can serve as a measure to differentiate between strong and weak electrolytes. Strong electrolytes produce a high concentration of ions, resulting in high conductivity. Weak electrolytes generate fewer ions and therefore exhibit lower conductivity. Nonelectrolytes, by definition, do not contribute to conductivity at all, as they do not produce ions in solution. Understanding the conductivity of a solution can provide invaluable information about the nature of the dissolved substances and their potential applications in various industries and scientific research.