If a crystal of KNO3 is added to a saturated water solution of KNO3 at 20°C, the added crystal will

Remain apparently unchanged

Explanation:

Such type of the solution in which the concentration of the solute is maximum and no more solute can be added is known as a saturated solution. In the given question the temperature is 20 degrees celsius that is fixed. So when the saturated solution is at fixed temperature then no extra solute can be dissolved. Thus the added crystal can not be dissolved and so remain in an unchanged condition. Any extra solute can be added in saturated solution only certain conditions such as when the temperature is increased for a certain time.