Part 3: Solubility and Complex lon Equilibria of Zinc and Magnesium Tons Both zic(II)ions and magnesium II)ions form insoluble hydrocade precipitates However, there hydroxide precipitates are quite different in their properties as this part of the experiment will show. For example, Zn(OH), forms (ZnOH). with excess of Pupalition of NH AN hydroxide precipitates dissolve in acid. Hydroxide precipitates that also dissolve in excess byrde e called amphoterie hydroxides. When sodium hydroxide is added to a solution of rietate, ZNO.. the following reaction occurs Zn(NOxhaq) + 2NaOH) ZOH).) INNO.(4) Write the complete ionic equation and the and to equation for the above reaction Complete ionic equation Net ionic equation: A magnesium ion solution has a similar reaction Me(NO) aq) + 2NaOH(aq) Mgom.) 2NaNO 24) Write the complete ionic equation and the net ionic aquation for the above reaction Complete ionic equation: Net ionic equation: Step 1: To cach of three test tubes, add about 2 ml. of 0.1 MZ(NO). To cach test tube add one drop of 6 M NaOH and stir. Record what you see below. Observation: Step 2: To the first test tube from Step 1 above, add 6 M HCl drop by drop with stirring. To the second test tube add 6 M NaOH, again drop by drop with stirring. To the third test tube, add 6 MNH, drop by drop with stirring. Record your observations below: Addition of HCI Addition of excess NaOH Addition of NH) Repeat steps 1 and 2 using a solution of 0.1 M Mg(NO). Record what you observe below. 1 Addition of 1 drop NaOH Addition of HCI Addition of excess NaOH Addition of NH; Below write the equations for each of the steps above. (Your instructor will write these on the chalkboard. Copy them carefully). For zinc hydroxide: The addition of HCI The addition of excess NaOH The addition of NH; For magnesium hydroxide: The addition of HCI The addition of excess NaOH The addition of NH From your observations above, how is Mg(OH), similar to Zn(OH);? From your observations above, how is Mg(OH), different from Zn(OH),? (Note that some cations form many complex ions and others do not.) Which metal hydroxide is an amphoteric hydroxide