[serotonin]

I have posted this before, I solved this and just wanted to ask if it looks correct. Thanks for any help :/ !!

Determination of total hardness: Direct titration. We titrate a solution containing calcium ions (Ca2+), volume 100 mL, with EDTA solution 0.1 M (moles/liter). The end point is determined at 10mL.
What is the equivalent point of the process? Based on the reaction, calculate the total hardness of the sample in mol /L CaCO3 and mg /L CaCO 3. Calculate the content of calcium ions (Ca 2+ ) as [Ca 2+ ] and the contents [EDTA ] and
[Ca2+ - EDTA] after adding 5mL of titrant. Explain based on reactions

I attached the file..