Question

The reaction between carbon tetrachloride, ccl4, and water, h2o, to form carbon dioxide, co2, and hydrogen chloride, hcl, has a δg∘ value of −232 kj/mole, and so is thermodynamically favored. but when you mix carbon tetrachloride with water, no change is observed. what is a possible explanation for this

Answer 1

The given reaction is:

CCl4 + 2H2O → CO2 + 4 HCl

The standard Gibbs free energy change for this reaction is, ΔG°= -232 kJ/mole. Since ΔG is negative, this implies that the above reaction must be spontaneous and thermodynamically favored.

However, the activation energy for this reaction is high. This implies that when CCl4 and H2O collide they need to overcome an energy barrier to form the products. In other words, although the reaction is thermodynamically favored it is not kinetically favored. The reaction might proceed at an extremely slow rate as a result of which no obvious change might be observed.