Question

is a KI/I2 (potassium and iodine) aqueous solution that is slightly yellow a homogeneous or heterogenous mixture? a crystal of Na2S2O3 is added and it sits for a minute and nothing happens, but when shaken it dissolves and becomes more clear. what kind of mixture (hetero or homo) is the result of this chemical reaction

Answer 1

answer:- I₂ is insoluble in water because it is non- polar and water is polar in nature. But when KI is added, it releases iodide ions ( I ^-) in water which reacts with I2 molecule to form I_{3​​​​​​} ^- ion which is soluble in water. Thus KI makes I2 soluble in water due to the formation of l3- ions.Due to this , dark brown colour of iodine in water becomes pale yellow because amount of free I2 molecules decreases.

As we add Na2S2O3 in KI/I2 solution the no. of I- ions increases in solution because Na2S2O3 act as a reducing agent for I2 molecules and thus , the solution becomes more clear homogenous solution ( homogeneous mixture).

Chemical reactions:-

I₂ + 2 Na₂S₂O_{​​​​​​​3   $\rightarrow$} 2 NaI + Na2S4O6

I- + I2 $\rightarrow$​​​​​​​ l3-

Answer 2

Homogeneous