Question

The equilibrium system between sulfur dioxide gas, oxygen gas, and sulfur trioxide gas is given.

Write the balanced chemical equation for the reverse reaction. Include physical states for all species.

Answer 1

The given chemical transformation,

Sulfur dioxide gas + Oxygen gas <-------------> Sulfur trioxide gas.

Chemical formulae for all the species are,

Sulfur dioxide gas (SO₂), Oxygen gas (O₂) and sulfur trioxide gas (SO₃).

Let us write them with their physical state in above chemical equation as,

SO₂ (g) + O₂ (g) <------------> SO₃ (g)

Balancing of chemical equatio:

We can see that S atoms are balanced on both side so let us balance O atoms on both sides.

Reactant side contains 4 O atoms and product side contains 3 O atoms.

Just on trial and error basis multiply SO2 on reactant side by 2 hence we get

2 SO₂ (g) + O₂ (g) <------------> SO₃ (g)

Now on reactant side there are 2 S and 6 O atoms and exactly half is the number on product side and hence product side is multiplied by 2 and finally all atoms are balance stoichometrically on both sides hence,

Balanced chemical equation for the formation of SO3 gas from SO2 gas and O2 gas is

2 SO₂ (g) + O₂ (g) <------------> 2 SO₃ (g)

For the reverse reaction i.e. decomposition of SO3 gas into SO2 gas and O2 gas is

2 SO₃ (g) <--------------> 2 SO₂ (g) + O₂ (g).

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