I'm having an issue solving a back titration problem. We need to identify the metal in a metal carbonate. It can either be a group 1A or 2A 1.8500 grams of the carbonate are diluted to .2500L and then 0.02000L is taken and mixed with 0.01500L of 0.1789M HCl in a flask. After shaking the mixture around 0.01756 L of 0.1013M NaOH was used to titrate the remaining HCl. I started this by first determining how many moles of HCl were added to the flask, and how much titrated with the NaOH: 0.01500L*0.1789M = 0.0026835 mol HCl total in flask 0.01756 L NaOH * 0.1013M x 1mol HCl/1mol NaOH = 0.001778828 mol HCl titrated. So 0.000904672 mols of the HCl reacted with the metal carbonate. From here I would go to determine how many mols of the carbonate there are, but I'm not sure how to do that. Writing the equation could turn out two different ways becuase I don't know how the metals are grouped. Just picking one and running with it gave me a molar mass of about 3400...not good. This is what I think the equation should be: M2CO3 + 2HCL -> H2CO3 + 2MCL2 How can I solve this?