The number of moles of $\mathrm{KI}$ required to prepare one mole of ${\mathrm{K}}_2\left[{\mathrm{HgI}}_4\right]$ is

According to the equation above, one mole of ${\mathrm{K}}_2\left[{\mathrm{HgI}}_4\right]$ is created when four moles of potassium iodide react with one mole of mercury iodide (potassium mercuric iodide).