The aqueous solution which has pH > 7 is Na\(_2\)CO\(_3(aq)\).
pH is a measure of the acidity or basicity of an aqueous solution. A pH of 7 indicates neutrality, while a pH greater than 7 indicates basicity or alkalinity. The pH of a solution is determined by the concentration of hydrogen ions (H\(^+\)) in the solution.
In the case of Na\(_2\)CO\(_3(aq)\), it is a basic compound because it has a carbonate ion, which can react with water to form hydroxide ions (OH\(^-\)). The hydroxide ions increase the concentration of hydroxide ions in the solution, which makes the solution basic.
The chemical reaction that occurs when Na\(_2\)CO\(_3(aq)\) dissolves in water is:
Na\(_2\)CO\(_3(aq)\) + H\(_2\)O → 2Na\(^+\) + CO\(_3^{2-}\) + 2OH\(^-\)
The presence of hydroxide ions in the solution makes it basic, and the higher the concentration of hydroxide ions, the higher the pH of the solution. Therefore, Na\(_2\)CO\(_3(aq)\) is the aqueous solution which has pH > 7.