A client is being admitted for hypernatremia. A nurse is preparing to administer 0.45% sodium chloride 500 mL IV to the client over 2 hours. The nurse should set the IV pump to deliver how many mL/hr?

The correct answer is C: 250 mL/hr. To calculate the rate for administering 0.45% sodium chloride at 500 mL over 2 hours, divide the total volume to be infused (500 mL) by the total time in hours (2 hours). This gives 250 mL/hr. Choice A (500 mL) is incorrect as it is the total volume, not the infusion rate per hour. Choice B (200 mL/hr) is incorrect as it is not the correct rate for the given volume over 2 hours. Choice D (100 mL/hr) is incorrect as it is half the correct rate. The correct answer, C, is derived from the calculation of total volume divided by total time, providing the appropriate infusion rate per hour.