Which of the following represents a strong electrolyte?

• HF

• Ca (NO3)2

• NH3

• СНзСН20Н

The strong electrolyte among the options is Ca(NO3)2.

A strong electrolyte is a substance that completely dissociates into ions when it is dissolved in water. Based on this definition, Ca (NO3)2 represents a strong electrolyte.

To determine which of the given compounds represents a strong electrolyte, we need to understand the definition of a strong electrolyte. A strong electrolyte is a compound that completely dissociates or ionizes into its constituent ions when dissolved in water. These ions can conduct electricity.

Now, let's examine each of the given compounds:

• HF (hydrofluoric acid): It is a weak electrolyte because it only partially ionizes in water. Therefore, it does not represent a strong electrolyte.

• Ca(NO3)2 (calcium nitrate): This compound contains calcium (Ca2+) and nitrate (NO3-) ions. When dissolved in water, it completely dissociates into its constituent ions. Since it fully ionizes into ions that can conduct electricity, it represents a strong electrolyte.

• NH3 (ammonia): Ammonia is a covalent compound that does not ionize in water. It does not dissociate into ions and, therefore, does not act as a strong electrolyte.

• СНзСН20Н (ethyl alcohol): Ethyl alcohol, also known as ethanol, is a molecular compound. It does not ionize in water and, hence, does not represent a strong electrolyte.

Therefore, among the given compounds, only Ca(NO3)2 represents a strong electrolyte.