14. Use the half reaction acidic solution method. MnO˜¯(aq) + Fe²+(aq) → Fe³ (aq) + Mn² (aq)

Gold can be dissolved from gold-bearing rock by treating the rock with sodium cyanide in the presence of oxygen. 4 Au(s) + 8 NaCN(aq) + O2(g) + 2 H2O() 4 NaAu(CN)2(aq) + 4 NaOH(aq) (a) Name the oxidizing and reducing agents in this reaction. What has been oxidized, and what has been reduced? (b) If you have exactly one metric ton (1 metric ton = 1000 kg) of gold-bearing rock, what volume of 0.075 M NaCN, in liters, do you need to extract the gold if the rock is 0.019% gold?

An electrolytic cell is set up with Cd(s) in Cd(NO3)2(aq) and Zn(s) in Zn(NO3)2(aq). Initially both electrodesweigh 5.00 g. After running the cell for several hours theelectrode in the left compartment weighs 4.75 g. (a) Which electrode is in the left compartment? (b) Does the mass of the electrode in the right compartmentincrease, decrease, or stay the same? If the masschanges, what is the new mass? (c) Does the volume of the electrode in the right compartment increase, decrease, or stay the same? If the volumechanges, what is the new volume? (The density of Cd is8.65 g/cm3.)

An electrode is prepared from liquid mercury in contact with a saturated solution of mercury(I) chloride, Hg2Cl, containing 1.00 M Cl . The cell potential of the voltaic cell constructed by connecting this electrode as the cathode to the standard hydrogen half-cell as the anode is 0.268 V. What is the solubility product of mercury(I) chloride?