Let's analyse each process for the change in entropy: A. When a liquid evaporates to a vapour, the molecules move from a more ordered liquid state to a highly disordered gaseous state. Therefore, entropy increases. B. When the temperature of a crystalline solid is lowered from 130 K to 0 K, the constituent particles lose kinetic energy and attain a more highly ordered state. At absolute zero (0 K), the entropy of a perfectly crystalline solid approaches zero. Therefore, entropy decreases. C. In the reaction 2NaHCO3(s) → Na2CO3(s) + CO2(g) + H2O(g), a solid reactant produces one solid and two gaseous products. The formation of gases greatly increases the disorder of the system. Therefore, entropy increases. D. In the reaction Cl2(g) → 2Cl(g), one mole of a gaseous molecule dissociates into two moles of gaseous atoms. Since the number of gaseous particles increases, the disorder of the system increases. Therefore, entropy increases. Thus, entropy increases in processes A, C, and D.