Dilute sulfuric acid, H2SO4(aq)\text{H}_2\text{SO}_4\text{(aq)}H2SO4(aq), can be electrolysed using inert electrodes.
Write a balanced ionic half-equation for the formation of hydrogen gas, H2\text{H}_2H2, at the negative electrode (cathode).
During the electrolysis, a volume of 60 cm360\text{ cm}^360 cm3 of oxygen gas, O2\text{O}_2O2, is collected at the positive electrode (anode).
Calculate the amount, in moles, of oxygen gas in 60 cm360\text{ cm}^360 cm3. (The volume of 1 mol1\text{ mol}1 mol of any gas at room temperature and pressure is 24 000 cm324\,000\text{ cm}^324000 cm3.)
Calculate the quantity of electricity, in coulombs, needed to produce this volume of oxygen gas from the half-equation:
2H2O→O2+4H++4e− 2\text{H}_2\text{O} \rightarrow \text{O}_2 + 4\text{H}^+ + 4\text{e}^- 2H2O→O2+4H++4e−(1 faraday=96 500 coulombs1\text{ faraday} = 96\,500\text{ coulombs}1 faraday=96500 coulombs)
Bromine reacts with sodium iodide solution. The equation for this reaction is:
Br2(aq)+2I−(aq)→2Br−(aq)+I2(aq) \text{Br}_2(\text{aq}) + 2\text{I}^-(\text{aq}) \rightarrow 2\text{Br}^-(\text{aq}) + \text{I}_2(\text{aq}) Br2(aq)+2I−(aq)→2Br−(aq)+I2(aq)This reaction can be described as both a displacement reaction and a redox reaction.
Identify the element that is displaced in this reaction.
Explain why this reaction is described as a redox reaction in terms of electron transfer.
Oxygen is also used in the industrial manufacture of sulfur trioxide, SO3\text{SO}_3SO3. The equation for this reaction is:
2SO2(g)+O2(g)⇌2SO3(g)ΔH=−197 kJ/mol 2\text{SO}_2(\text{g}) + \text{O}_2(\text{g}) \rightleftharpoons 2\text{SO}_3(\text{g}) \quad \Delta H = -197\text{ kJ/mol} 2SO2(g)+O2(g)⇌2SO3(g)ΔH=−197 kJ/molWhat does the ⇌\rightleftharpoons⇌ symbol indicate about this reaction?
Predict and explain the effect of increasing the temperature on the equilibrium position of this reaction.
