A substance that dissolves only partially in water and forms an equilibrium with its ions is best described as a:

A substance that dissolves only partially in water and forms an equilibrium with its ions is best described as a:

• A. Strong electrolyte
• B. Non-electrolyte
• C. Weak electrolyte
• D. Pure compound

Answer: (C)

When a substance dissolves, it can either break apart into ions completely or only partway, leaving some undissociated molecules in solution. A weak electrolyte is defined by this partial ionization in water, where an equilibrium exists between the dissolved molecules and the ions: some of the dissolved species are ionized, and some remain as molecules. This ongoing balance is what makes the solution conduct electricity, but not as strongly as a solution where all dissolved species are fully ionized. If a substance dissolved and produced no ions, it would be a non-electrolyte; a pure compound describes the substance’s composition but not how it behaves in water. The description given—dissolves only partially and forms an equilibrium with its ions—best fits a weak electrolyte.

When a substance dissolves, it can either break apart into ions completely or only partway, leaving some undissociated molecules in solution. A weak electrolyte is defined by this partial ionization in water, where an equilibrium exists between the dissolved molecules and the ions: some of the dissolved species are ionized, and some remain as molecules. This ongoing balance is what makes the solution conduct electricity, but not as strongly as a solution where all dissolved species are fully ionized. If a substance dissolved and produced no ions, it would be a non-electrolyte; a pure compound describes the substance’s composition but not how it behaves in water. The description given—dissolves only partially and forms an equilibrium with its ions—best fits a weak electrolyte.