Final answer:
The state of water, whether it be solid, liquid or gas, is primarily determined by temperature. As temperature changes, so too does the kinetic energy of water molecules, leading to changes in state. Thus, of the options (pH, Chlorinity, Temperature, Salinity, Density), temperature is the key factor.
Step-by-step explanation:
The primary factor that determines the states of matter in which
water exists
is
temperature
. Water, like many other substances, can exist in three primary states of matter - solid (ice), liquid (water at room temperature), and gas (steam or water vapor). The change between these states is mainly influenced by temperature, this is due to the kinetic energy of the water molecules which increases or decreases with temperature. For example, if we increase the temperature of ice (solid water), the kinetic energy of water molecules increases leading to the ice melting into liquid water. Conversely, if the temperature of water decreases, its kinetic energy also decreases, resulting in the water freezing into ice. At even higher temperatures, liquid water will evaporate and become water vapor (a gas) due to increased molecular motion. So, among the options given: pH, Chlorinity, Temperature, Salinity, and Density,
Temperature
is the key determinant of the state of water.
Learn more about States of Water