Determine the lime and soda ash dose, in mg/L as CaCO3, to soften the following water to a final hardness of 120.0 mg/L as CaCO3. If the price of lime, purchased as CaO, is $61.70 per megagram (Mg), and the price of soda ash, purchased as Na₂CO3, is $172.50 per Mg, what is the annual chemical cost of treating 1.35 m³/s of this water? Assume the lime is 87 percent pure and the soda ash is 97 percent pure. The ion concentra- tions reported below are all mg/L as CaCO3. Ca²+ = 293.0 Mg²+ 55.0 HCO3 301.0 CO₂ = 3.0 Question 6 1 pts Problem 6-24: How much soda ash, in mg/L as CaCO3, will need to be added? 1 pts Question 7 Problem 6-24: Convert your answer for the previous problem to mg/L of Na2CO3, as purchased (accounting for the less than 100% purity).