Can you please help me??! Chemistry problem: Identifying a solution containing ions of an unknown element X based on the results of three tests? Multiple choice

Question

A solution containing ions of an unknown element X is divided into 3 samples. The following tests were performed on samples of the solution.

Sample Test Observation
1 Add H+ (aq) No Change
2 ADD OH-(aq) No Change
3 Add SO4-2 (aq) No Change

A. Pb + 2 (aq) B. Al + 3 (aq) C. Ba +2 (aq) D. Na + (aq) E. CO3 -2 (aq)

Can you please help me? I need to learn why the correct answer is correct. I am just not sure how what to look for when trying to solve this. Is the fact there is no reaction for all three samples important? I think it is.

Thank you so much!

Answer 1

Na+

 

Na+ is soluble in aqueous solution. If OH- or SO4 -2 were to react with Na+, the ions would still be soluble. In the other cases, precipitation occurs with the addition of at least one of the ions.