Question

in a solution, which pair of actions could combine to keep a concentration constant? (1 point)
adding water, then removing solution
adding solute, then evaporating water
adding water, then adding solute
adding solute, then removing solution

Explanation:

Concentration is amount of solute per amount of solution. Adding solute increases solute amount, and removing solution in proportion (as long as the solution is homogeneous) keeps the ratio of solute to solution constant. Adding water dilutes, adding solute without adjusting volume increases, and evaporating water after adding solute also increases concentration.

Answer:

adding solute, then removing solution