Which of the following is a property of a strong electrolyte?

The property of a strong electrolyte is that it dissociates completely into ions in solution. When a strong electrolyte, such as sodium chloride, is dissolved in water, it breaks apart fully into its constituent ions, which allows the solution to conduct electricity efficiently. This complete dissociation is crucial because it means that all of the solute has converted into charged particles (ions) that are free to move and carry an electric current.

In contrast, options that imply partial dissociation or lack of conductivity do not accurately describe strong electrolytes. For instance, some substances may only partially dissociate and would be categorized as weak electrolytes, leading to limited conductivity. Additionally, substances that do not conduct electricity at all would be non-electrolytes, which are not characterized by the properties of strong electrolytes. The reactivity of an electrolyte does not inherently define its strength as an electrolyte; thus, the speed of reaction with other compounds is unrelated to its classification as a strong electrolyte. Therefore, the defining feature here is the complete dissociation into ions, making option B the correct choice.