Using circles to represent cations and squares to represent anions, show pictorially the reactions that occur between aqueous solutions of (a) \(\mathrm{Ba}^{2+}\) and \(\mathrm{OH}^{-}\) (b) \(\mathrm{Co}^{3+}\) and \(\mathrm{PO}_{4}^{3-}\)

In this reaction, the \(\mathrm{Ba}^{2+}\) ion (circle with a 2+ charge) will combine with two \(\mathrm{OH}^{-}\) ions (squares with a 1- charge) to form a more stable compound - barium hydroxide, \(\mathrm{Ba}(\mathrm{OH})_{2}\). The balanced equation for this reaction is: \(\mathrm{Ba}^{2+} + 2\mathrm{OH}^{-} \rightarrow \mathrm{Ba}(\mathrm{OH})_{2}\) To represent this pictorially, draw a circle labeled "Ba" with a 2+ charge, and two squares labeled "OH" with a 1- charge each. Draw arrows between them to show the interactions, leading to a final structure combining the circle and two squares: [Circle (Ba, 2+)] →← [Square (OH, 1-)] ↓ [Circle (Ba, 2+)] →← [Square (OH, 1-)] In the completed image, the circle representing the Ba ion will be linked to both squares representing the OH ions, forming a unit of barium hydroxide.

In this reaction, the \(\mathrm{Co}^{3+}\) ion (circle with a 3+ charge) will combine with the \(\mathrm{PO}_{4}^{3-}\) ion (square with a 3- charge) to form a more stable compound - cobalt phosphate, \(\mathrm{Co}_{3}(\mathrm{PO}_{4})_{2}\). The balanced equation for this reaction is: \(2\mathrm{Co}^{3+} + 3\mathrm{PO}_{4}^{3-} \rightarrow \mathrm{Co}_{3}(\mathrm{PO}_{4})_{2}\) To represent this reaction pictorially, draw two circles labeled "Co" with a 3+ charge and three squares labeled "PO4" with a 3- charge. Draw arrows between them to show the interactions, leading to a final structure combining the two circles and three squares: [2 Circles (Co, 3+)] →← [3 Squares (PO4, 3-)] In the completed image, two circles representing the cobalt ions will be combined with three squares representing the phosphate ions, forming a unit of cobalt phosphate.