Recently, I've run an experiment about the effect of reducing concentration on rate of a reaction.

Here's the chemical reaction:

$\ce{10 NaHSO3 + 4 KIO3 ⇌ 5 Na2SO4 + 2 I2 + 3 H2SO4 + 2 K2SO4 + 2 H2O}$

I ran three tests:

  1. $10$ cc $\ce{KIO3}$ Solution + $10$ cc $\ce{NaHSO3}$ solution _ Time: $163$ sec

  2. $10$ cc $\ce{KIO3}$ Solution + A $6$ cc $\ce{NaHSO3}$ and $4$ cc water solution _ Time: $320$ sec

  3. $10$ cc $\ce{KIO3}$ Solution + A $4$ cc $\ce{NaHSO3}$ and $6$ cc water solution _ Time: $713$ sec

I calculated the molarity of $\ce{NaHSO3}$ in each test and also calculated the rate of each test using the formula : $\frac{[\ce{NaHSO3}]}{t}$

Now the question is how can I know the kinetic order of this reaction?

I mean with only 3 numbers of concentration, I cannot draw a curve. Is there any other way to know the kinetic order?

Edit: I hope you already know that the curve of concentration according to time shows the kinetic order of reaction. It's just with 3 data you cannot draw an accurate curve.

  • $\begingroup$ Is cc an abbreviation for cubic centimetre, i.e. mL? $\endgroup$ Apr 10, 2017 at 5:18
  • $\begingroup$ Yes cc is cubic centimitre, maybe I should've written mL (mililitre). $\endgroup$ Apr 10, 2017 at 6:29
  • 1
    $\begingroup$ What do the times you give represent ? How did you obtain them? $\endgroup$
    – porphyrin
    Apr 10, 2017 at 7:30
  • $\begingroup$ The time to see the I2 blue colour. It means by reducing the concentration of NaHSO3, the rate of reaction also reduces. In other words, it takes more time to see the result. I've already said I ran the tests myself. $\endgroup$ Apr 11, 2017 at 16:11
  • $\begingroup$ Are you allowing for the possibility of a complex reaction mechanism and thus a fractional or negative reaction order? If not and you are just trying to choose between zero, first, and second order, it would seem to be closest to linear. $\endgroup$
    – Tyberius
    Apr 13, 2017 at 1:35


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