3. Answer ALL parts (a) to (h). (a) Compare the acidity of the two aqueous oxoacids tabulated below and give reasons for

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3 Answer All Parts A To H A Compare The Acidity Of The Two Aqueous Oxoacids Tabulated Below And Give Reasons For 1 (165.56 KiB) Viewed 66 times

3. Answer ALL parts (a) to (h). (a) Compare the acidity of the two aqueous oxoacids tabulated below and give reasons for the difference in pKa values at 298 K. [Word limit=100] [4%] OH 0= OH nitrous acid pka = 3.3 nitric acid pka = -1.4 (b) Calculate the pH of an aqueous nitrous acid (HNO₂) solution of concentration 0.20 mol dm-³. Justify any assumptions made in your calculation. The dissociation constant, K₂, for nitrous acid is 4.7 x 104 at 298 K. [4%] (c) Calculate the pH of an aqueous buffer solution containing 0.20 mol dm-³ nitrous acid and 0.40 mol dm-³ sodium nitrite (NaNO2) at 298 K. State any assumptions that you make in your calculation. [3%] (d) Silver bromide, AgBr, is a sparingly soluble salt in water. Write down expression for the solubility product, Ksp, of silver bromide. [1%] (e) Calculate the molar solubility of AgBr in water, given that Ksp = 5.0 x 10-13 at 298 K. [2%] (f) Consider the gas phase reaction between nitrogen and hydrogen, forming ammonia. In a sealed reaction chamber the system exists in dynamic equilibrium. Experimental measurements performed at 450 K show that the reaction is exothermic. 450 K N2 (g) + 3 H2(g) 2 NH3(g) (AH, = -92 kJ mol-¹) 1 atm Write an expression for the equilibrium constant, K. You may use either the gas concentrations (mol dm-³), or partial pressures (bar), when forming this expression. [2%] (g) Predict the change in the position of equilibrium if the temperature of the reaction vessel is raised to above 450 K. [2%] (h) Predict the change in the position of equilibrium if the total pressure inside the reaction vessel is increased. [2%]