A 10.0 mL sample of supernatant liquid from the system described by equation 1 was titrated with 0.01022 M EDTA solution to an end-point at 16.90 mL. Titration of the blank gave a titre (end-point) at 1.45 mL. Determine the titration volume required to titrate the Ca2+ alone.

To determine the titration volume required to titrate the Ca2+ alone, we need to consider the reaction between Ca2+ ions and EDTA. The reaction can be represented as:

Ca2+ + EDTA ↔ Ca-EDTA

From the given information, we know that the supernatant liquid contains Ca2+ ions along with other species that can also react with EDTA. So, when we titrate the supernatant liquid with EDTA, we are not only titrating the Ca2+ ions but also other species present in the solution.

To find the titration volume required for Ca2+ alone, we need to find the volume of EDTA solution that reacted with the other species present in the supernatant liquid. This can be calculated by subtracting the volume of EDTA solution that reacted with the blank (titration of the blank) from the volume of EDTA solution that reacted with the supernatant liquid.

Here's how to calculate the titration volume required for Ca2+ alone:

1. Calculate the volume of EDTA solution that reacted with the supernatant liquid:
Titration volume for supernatant liquid = Volume at end-point - Volume at blank
Titration volume for supernatant liquid = 16.90 mL - 1.45 mL

2. Subtract the titration volume for supernatant liquid from the total titration volume to get the titration volume for Ca2+ alone:
Titration volume for Ca2+ alone = Titration volume for supernatant liquid - Titration volume for blank

By following these steps, you can determine the titration volume required to titrate the Ca2+ ions alone.