Answer :
Double replacement reaction : It is a type of reaction in which a positive cation and a negative anion of the reactants react to give a new compound as a product.
[tex]AB+CD\rightarrow AD+CB[/tex]
In this, A and C are the cations and B and D are the anions.
When one mole of potassium hydroxide react with the one mole of zinc chloride to give one mole of zinc hydroxide and 2 moles of potassium chloride.
The balanced chemical reaction is,
[tex]KOH+ZnCl_2\rightarrow Zn(OH)_2+2KCl[/tex]