‘Double displacement reactions’ are commonly observed insolutions and aqueous phase. They are less common in solidphase and generally requires high temperature to take place.However, in this article, we report double displacement reactionstaking place in solid phase at room temperature. Wealso highlight the criteria required for the occurrence of displacementreactions in solid state at room temperature. Thedriving force for all the double displacement reactions is explainedusing Pearson’s hard and soft acid and base (HSAB)concept, and in few cases involvement or aid of water of hydrationis observed.