You are using pure limestone (CaCO₃)to provide the calcium needed to exchange with acid cations in a soil with a maximum potential cation exchange capacity of 20 cmol_c/kg.How many kg of this limestone would you need to add to a hectare furrow slice (2.0 x 10⁶ kg)to reduce the percentage acid saturation from 40 to 10%,assuming that all the calcium added exchanged with aluminum or hydrogen ions? A)20,000 B)50,000 C)12,000 D)6,000 E)8,000

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To calculate the amount of limestone needed, first determine the change in acid saturation required, which is from 40% to 10%, a 30% reduction. The cation exchange capacity (CEC) is 20 cmol_c/kg. The total exchange capacity for the hectare furrow slice (2.0 x 10^6 kg) is 20 cmol_c/kg * 2.0 x 10^6 kg = 40 x 10^6 cmol_c. A 30% reduction means 0.3 * 40 x 10^6 cmol_c = 12 x 10^6 cmol_c of Ca^2+ is needed. Since each mole of CaCO3 provides one mole of Ca^2+, and the molar mass of CaCO3 is approximately 100 g/mol, the mass of limestone needed is 12 x 10^6 cmol_c * 100 g/mol = 1.2 x 10^9 g, or 1.2 x 10^6 kg, which is 1200 kg. However, given the options, there seems to be a mistake in the calculation or interpretation of the options. The correct approach involves calculating the change in acid saturation and converting that to the amount of CaCO3 needed, but none of the provided options accurately reflects the correct calculation based on the given data and standard assumptions. Re-evaluating the calculation steps for accuracy and considering the context might suggest an error in the interpretation of the options or a mistake in the calculation process.

You Are Using Pure Limestone (CaCO3)to Provide the Calcium Needed

You Are Using Pure Limestone (CaCO₃)to Provide the Calcium Needed