Question

question 8
using the solubility rules located on your \green sheet\, determine if it is soluble or insoluble in water, and the corresponding phase symbol.
ionic compound | soluble in water?
mgo | select an answer
znco₃ | select an answer
mg₃(po₄)₂ |
ba(clo₄)₂ | insoluble, (s)
pbs | soluble, (aq)
al(no₃)₃ |
cos | insoluble (aq)
cui | soluble, (s)
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Explanation:

Step1: Recall Solubility Rules for MgO

Metal oxides (like MgO) are generally insoluble in water (they react with water to form hydroxides, but as a solid oxide, it's insoluble in water). So MgO is insoluble, phase symbol (s).

Step2: Recall Solubility Rules for ZnCO₃

Carbonates (except for Group 1 and ammonium) are insoluble. Zn is not Group 1, so ZnCO₃ is insoluble, (s).

Step3: Recall Solubility Rules for Mg₃(PO₄)₂

Phosphates (except for Group 1 and ammonium) are insoluble. Mg is Group 2, not Group 1, so Mg₃(PO₄)₂ is insoluble, (s).

Step4: Correct Errors in Given Compounds (Optional, for Learning)

• Ba(ClO₄)₂: Perchlorates are soluble, so it should be soluble, (aq) (not insoluble (s)).
• PbS: Sulfides (except Group 1, 2, ammonium) are insoluble, so PbS is insoluble, (s) (not soluble (aq)).
• Al(NO₃)₃: Nitrates are soluble, so soluble, (aq) (correct as given).
• CoS: Sulfides are insoluble, so insoluble, (s) (not (aq)).
• CuI: Iodides (except Group 1, 2, ammonium, and some exceptions like AgI, PbI₂, CuI is insoluble), so insoluble, (s) (not soluble (s)). But the question is to determine for the first three (and correct the given if needed, but the main task is to answer the "Select an answer" for MgO, ZnCO₃, Mg₃(PO₄)₂).

Answer:

s (for each "Select an answer"):

• MgO: insoluble, (s)
• ZnCO₃: insoluble, (s)
• Mg₃(PO₄)₂: insoluble, (s)

(Note: If the question is to correct the existing wrong ones too, the corrected ones would be:

• Ba(ClO₄)₂: soluble, (aq)
• PbS: insoluble, (s)
• CoS: insoluble, (s)
• CuI: insoluble, (s)

But the primary task here is to answer the "Select an answer" for the first three, so focusing on those.)