For the reaction given below: CoCl _ 3 . xNH _ 3 + AgNO _ 3 (aq) →...

{CoCl}_{3 .}{xNH}_{3} + {AgNO}_{3} \to \mathop{AgCl ↓}_{2mol}$</p><p>For 2 moles of AgCl precipitate out,only two chloride ions should be present out side the coordination sphere that is in the ionization sphere.</p><p>Hence, the formula of the complex should be$\left[Co{\left({NH}_{3}\right)}_{5}Cl\right]{Cl}_{2}$</p><p>\left[Co{\left({NH}_{3}\right)}_{5}Cl\right]{Cl}_{2} + {AgNO}_{3} \to \mathop{AgCl ↓}_{2mol}$

So, the value of x should be 5.

$x = 5$.