Question

What is the molarity of a potassium triiodide solution, ki3(aq), if 30.00 ml of the solution is required to completely react with 25.00 ml of a 0.200 m thiosulfate solution, k2s2o3(aq)? the chemical equation for the reaction is 2 s2o32-(aq) + i3-(aq) → s4o62-(aq) + 3 i-(aq). what is the molarity of a potassium triiodide solution, ki3(aq), if 30.00 ml of the solution is required to completely react with 25.00 ml of a 0.200 m thiosulfate solution, k2s2o3(aq)? the chemical equation for the reaction is 2 s2o32-(aq) + i3-(aq) → s4o62-(aq) + 3 i-(aq). 0.167 m 0.333 m 0.120 m 0.0833 m?

Answer 1

Answer: 0.083 M

Explanation:

`2S_2O_3^(2-)(aq)+I_3^-(aq)\rightarrow S_4O_6^(2-)(aq) + 3I^-(aq)`

Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.

`Molarity=\frac{moles}{\text {Volume in L}}`

moles of
`K_2S_2O_3=Molarity* {\text {Volume in L}}=0.200* 0.025=5* 10^(-3)moles`

According to stoichiometry: 2 moles of
`2S_2O_3^(2-)(aq)` require 1 mole of
`I_3^-`

Thus
`5* 10^(-3)moles` require=
`(1)/(2)* 5*10^(-3)=2.5* 10^(-3)` moles of
`I_3^-`

Thus Molarity of
`I_3^-=(2.5* 10^(-3))/(0.030L)=0.083M`