Group the following four terms into two pairs according to how the terms are related, and explain how they are related: end point, standard solution, titrant, and transition range.

In the context of a titration process in chemistry, 'End Point' is the point during a titration where a reaction has reached its completion. 'Standard Solution' refers to a solution with a known concentration. 'Titrant' is the solution in the burette that is used to react with a substance in a solution to find its concentration. Finally, 'Transition Range' refers to the pH range where the indicator changes its color.

From the definitions, the four terms can be grouped into the following two pairs: [End Point, Transition Range] and [Standard Solution, Titrant].

End Point and Transition Range: Both of these terms are related because they are connected with the point at which the titration should end. The end point indicates when the titration is complete, as visually indicated by the color change of the indicator, which specifically occurs in the transition range of the indicator. Standard Solution and Titrant: A standard solution and the titrant in the process of titration have similar roles, as they represent the known factors in the reaction. The titrant is the solution of known concentration that is added to react with a solution to find its concentration. The standard solution, on the other hand, is a solution of accurately known concentration, used as a reference.