Magnesium carbonate scale inside industrial boilers can be converted into an easily…
CHEMISTRY · Multi-part · A Level · Chemistry · Reactions of ions in aqueous solution · AP
Problem
Magnesium carbonate scale inside industrial boilers can be converted into an easily removable solid using the following two-step treatment carried out at 100 °C and atmospheric pressure.
Step 1 Powdered MgCO₃(s) is sprayed with dilute HCl(aq) until bubbling ceases and the solid dissolves completely.
Step 2 A separate aqueous stream containing Na₃PO₄ is then mixed with the acidic solution from step 1, producing a new solid that is filtered out.
(Given solubility information: Mg₃(PO₄)₂ is insoluble in water; the other products of step 2 remain in solution.)
(a) Write the molecular equation, the complete ionic equation, and the net ionic equation for step 1.
(b) Write the net ionic equation for step 2.
(c) Combine your results from parts (a) and (b) to obtain the overall net ionic equation for the two-step process, showing clearly which species cancel.
(d) Explain why the treatment is effective for scale removal, referencing the physical states of reactants and products in each step.