Sulfur oxides are key intermediates in the industrial production of sulfuric acid

CHEMISTRY · Multi-part · CBSE · Chemistry · Equilibrium · Equilibrium

Problem

Sulfur oxides are key intermediates in the industrial production of sulfuric acid. Two elementary equilibria and the overall reaction of interest are shown below (all species are gases, temperature is 298 K): Step I:

\mathrm{SO}_2 + \frac{1}{2}\,\mathrm{O}_2 \leftrightarrow \mathrm{SO}_3 \quad K_I = 4.7 \times 10^{24}

Step II:

2\,\mathrm{SO}_3 \leftrightarrow \mathrm{S}_2\mathrm{O}_6 \quad K_{II} = \; ?

(unknown) Overall:

2\,\mathrm{SO}_2 + \mathrm{O}_2 \leftrightarrow \mathrm{S}_2\mathrm{O}_6 \quad K_{\text{overall}} = 3.0 \times 10^{25}

Answer the following. (1) Part 1: (a) Using the two elementary steps, show how they combine to produce the overall reaction. Clearly indicate any reversal or scaling of a step that is required. (2) Part 2: (b) Determine the numerical value of

K_{II}

. Show all algebraic steps leading to your answer. (3) Part 3: (c) The value of

K_{II}

differs markedly from that of

K_I

. Explain what this difference implies about the relative positions of the two individual equilibria when the system reaches overall equilibrium.

Related theory

Browse the problem library