Ca +NH CO CaCO +2NH + +2 4 2 3 3 4 White ppt. CaCO +2CH COOH CH COOCa+ HO +CO 3 3 3 2 2 2 CH COOCa+ NH CO CaCO +2CH COONH 4 2 4 3 4 3 2 2 4 2 White ppt. Mg +2