Essential to public health is potable water. Calculate the amount of chlorine needed to disinfect 50 ML water to a residual dose of 0.3 mg/L. You need to add an additional 0.4 mg/L to the water in order to reach the breakpoint for chlorine addition based upon jar tests for this particular drinking water. Explain what the breakpoint is and why you would want a residual 0.3 mg/L of chlorine in your water.