<span>it tells you the sequence in which events occurred, not how long ago they occurred.</span>
1) endothermic
2)exotgermic
3)exotgermic
The molarity of a solution : 0.4 M
<h3>Further explanation</h3>
Given
0.2 moles of Potassium Oxide
500 ml of water = 0.5 L
Required
The molarity
Solution
Molarity is a way to express the concentration of the solution
Molarity shows the number of moles of solute in every 1 liter of solution or mmol in each ml of solution

Assume volume of solution = volume of water(addition of solution volume from volume Potassium Oxide is negligible
Input the value :
M = 0.2 : 0.5
M = 0.4
Answer:
ion exchange is the exchange of ions of the same charge between an insoluble solid and a solution in contact with it, used in water-softening and other purification and separation processes.
Explanation:
hope this helped !