Mix dry Al_2 (SO_4), and dry NaHCO_3, Is there a reaction? ___ Add a few ml of H
ID: 522681 • Letter: M
Question
Mix dry Al_2 (SO_4), and dry NaHCO_3, Is there a reaction? ___ Add a few ml of H_2 O to the above mixture. Is there a reaction? _____ Give the evidence for the reaction: ____ Write a net - ionic equation to show the hydrolysis is reaction of Al^3+ Net - ionic equation: _____ Is the solution acidic or basic? Write a net - ionic equation to show the reaction of the produced H^+ with the added HCO_3^-. Net - ionic equation: ________ Write an equation to show the formation of the produced gas. Equation: ______ Add the three equations above. Drop out terms that appear on both sides, to obtain the net -ionic equation of the overall reaction. Net - ionic equation: ________ You have tested experimentally the pH of 0.10 M NaH_2 PO_2 solution. How would you determine theoretically whether it is acidic or basic? Given: K_al for H_3 PO_4 = 6.9 times 10^-3, for H_2 PO_4^- = 6.3 times 10^-8 a) H_2 PO_4^- + H_2 O + OH^- K_b for H_2 PO_4^- = K_w K_al for H_3 PO_4^- b) H_2 PO_4^- + H_2 O + H_3 O^+ K_b for H_2 PO_4^- = ____ Compare the K values for the above equilibrium reactions, hence predict whether the solution is acidic or basic. Answer: ________ Check your answer against the measured value of 0.10 M NaH_2 PO_4 on page 5. The measured pH value is ____; J the solution is ______. (acidic, or basic)Explanation / Answer
2. (i) Net Ionic reaction,
Al3+ + HCO3- + SO4-= Al2(SO4)3 + H+ + CO3-
2 (ii) Net solution is acidic because it contains lot of H+ ions and from lewis theory of acid, if a solution conatins H+ ion in big amount, it will cause solution to behave as acidic.
2 (iii) Al3+ + 6 HCO-3 + 6 O2 = 2 Al(OH)3 + 3 SO2-4 + 6 CO2 + H+
This equation also shows that some amount of carbon dioxide is also formed.