Seawater, which covers the majority of the earth, is composed primarily of molecules of H2O and equal numbers of Na ions and Cl- ions. Suppose we have a thoroughly mixed solution (containing these species only) at 25oC. How many components and how many phases are in such a system?

Explanation:

Species present are , and . Now, we will calculate the number of componenets present as follows.

                C = n - E

where,   E = number of independent equations

              n = number of phases present

Therefore, we will calculate the number of components as follows.

                        C = 3 - 1

                            = 2

Since, sodium chloride (NaCl) will tend to form a homogeneous mixture in water. Therefore, phase will be equal to 1.

Therefore, it means that there are two components present in one phase.