The correct option is this: TWO STEPS OF THE PROCESS ARE ENDOTHERMIC AND ONE STEP IS EXOTHERMIC.
The enthalpy change of solution refers to the heat change that occur when a substance is dissolved in a solvent.
Dissolving a substance in a solvent involves three distinct steps:
1. the breaking of the inter molecular forces that is holding the substance together. This process is endothermic because it needs energy to occur, therefore its enthalphy change is greater than zero.
2. The breaking of inter molecular forces that is holding the solvent molecules together. This process is also endothermic.
3. The mixing together of the solute and the solvent. The reaction is an exothermic reaction because energy is given off as the molecules bond togeher. <span />
An Arrhenius base is a substance that are being dissolves in water dissociate and gives Hydroxide ions. (OH⁻)
Marie Curie in 1898
Hope this helps