Chapter 4
Q. 4.2
Write a net ionic equation for any precipitation reaction that occurs when dilute solutions of the following ionic compounds are mixed.
(a) NaOH and Cu(NO_{3})_{2} (b) Ba(OH)_{2} and MgSO_{4} (c) (NH_{4})_{3}PO_{4} and K_{2}CO_{3}
STRATEGY
1. Follow the plan:
Figure 4.3: compound → ions → possible precipitates
possible precipitates → (Figure 4.2) → insoluble compound → net ionic equation
2. In writing the net ionic equation, start with the insoluble compound on the right, then write the component ions on the left. Do not forget the physical states: ions (aq), product (s).
Step-by-Step
Verified Solution
| Na^{+} and OH^{-} from NaOH; Cu^{2+} and NO^{-}_{3} from Cu(NO_{3})_{2}
NaNO_{3} and Cu(OH)_{2} NaNO_{3} is soluble; Cu(OH)_{2} is insoluble. Cu^{2+}(aq) + 2OH^{-}(aq) → Cu(OH)_{2}(s). |
(a) Ions in solution Possible precipitates Solubility Net ionic equation |
| Ba^{2+} and OH^{-} from Ba(OH)_{2}; Mg^{2+} and SO^{2-}_{4} from MgSO_{4}
Mg(OH)_{2} and BaSO_{4} Both BaSO_{4} and Mg(OH)_{2} are insoluble. Mg^{2+}(aq) + 2OH^{-}(aq) → Mg(OH)_{2}(s) Ba^{2-}(aq) + SO^{2-}_{4}(aq) → BaSO_{4}(s) |
(b) Ions in solution Possible precipitates Solubility Net ionic equation |
| NH^{+}_{4} and PO_{4}^{3-} from (NH_{4})_{3}PO_{4}; K^{+} and CO_{3}^{2-} from K_{2}CO_{3}
(NH_{4})_{2}CO_{3} and K_{3}PO_{4} Both (NH_{4})_{2}CO_{3} and K_{3}PO_{4} are soluble. no reaction |
(c) Ions in solution Possible precipitates Solubility Net ionic equation
|