溶解 (róng jiě) specifically means 'to dissolve' as a solute in a solvent, like salt dissolving in water. 融化 (róng huà) means 'to melt' by heat and can also mean 'to dissolve' in a broader, often metaphorical sense. Unlike 解散 or 解体, 溶解 is only used for physical/chemical dissolution, not for organizations or groups.