While servicing a cooling tower you notice there`s a slight build-up of scale in the tower sump. To reduce the amount of work it will require later, you decide to use a mild acidic solution to remove the scale. The solution contin ues to circulate while you change the filters and check the belts in the air handler. After testing the water you realize that the acidic condition of the water needs to be neutralized. Which of the following is acidic?

While servicing a cooling tower you notice there`s a slight build-up of scale in the tower sump. To reduce the amount of work it will require later, you decide to use a mild acidic solution to remove the scale. The solution contin ues to circulate while you change the filters and check the belts in the air handler. After testing the water you realize that the acidic condition of the water needs to be neutralized. Which of the following is acidic?