This is the net ionic equation for the formation of calcium hydroxide, Ca(OH)2 precipitate from soluble calcium ions and soluble hydroxide ions.
The balanced equation is Ca(OH)2 + H2SO4 → CaSO4 + 2H2O.
If you mean Ca(OH)2(s) --> Ca2+(aq) + 2OH-(aq) this is the equation for the dissolving of calcium hydroxide in water.
A Double displacement reaction or Neutralization reaction
this is an exotermic reaction
This reaction is called hydrolysis.
A and B
A combustion reaction
This reaction is called photosynthesis.
It's a chemical reaction.
The reaction shows calcium ions (Ca2+) reacting with hydroxide ions (OH-) to form solid calcium hydroxide (Ca(OH)2) and release heat of 16.71 kJ. This reaction is exothermic, as indicated by the negative enthalpy change.
No reaction
I suppose that you think to synthesis reaction.