Reaction rate for hydrogen peroxide with acidic iodine ion

Objectives

Student can observe the reaction rate for hydrogen peroxide with the acidic iodine ion and understand the right precipitation technique

Introduction

The rate of reaction is defined as the change of concentration of a reactant or a product per unit time.

Equipment

·       #  100 ml of volumetric flask

·       # 100 ml and 250 ml beaker

·       #  50 ml burette

·       #  Stop watch

·       #  Conical flask

·       #  Stopper

·       #  10 ml and 25 ml pipette

·       #  10 ml and 100 ml measuring cylinder

Reagent

·         # Distilled water

·         # 20 g/ 100 ml H2O2

·         # 2.0 M H2SO4

·         #Starch

·         #25 g/L KI solution

·         #0.1M Na2S2O3

Procedure

1.    1. 100 ml of 0.5M sodium thiosuphate solution was prepared in 100 ml volumetric flask (A) and the solution was poured into burette (A).

2.    2. 25 g per L aqueous potassium iodine filled into burette (B)

3.    3. 100 ml of 0.1 M hydrogen peroxide, H2O2 from the 20 g/ 100 ml stock solution using volumetric flask. The volumetric flask was labeled with (C) and sealed properly to prevent from contamination with air.

4.    4. 10 ml H2O2 solution pipetted into a dry and clean conical flask. 10 ml 2.0 M diluted sulfuric acid solution, 5 ml starch solution and 15 ml of distilled water. Then, 5 ml of starch solution added from burette A, and shaken until homogenous.

5.    5. 20 ml potassium iodine solution was transferred from burette B to a small beaker.

6.  6.The potassium iodine solution mixed quickly with previous mixture in the conical flask. The flask shaken slowly until homogenized. The duration of the  mixture to turn blue noted down.

7.   7. The previous method repeated by changing the volume of distilled water and potassium iodine like table below

H2O2 (ml)	H2SO4 (ml)	Starch (ml)	Water (ml)	Na2S203	KI (v) (ml)
10	10	5	15	1	20
10	10	5	20	1	15
10	10	5	25	1	10
10	10	5	30	1	5

            Table 1.0

8.    Plot the graph :

a)    V α t

b)    V α 1/t

c)    Vt α 1/t

Result

H2O2 (ml)	H2SO4 (ml)	Starch (ml)	Water (ml)	Na2S203	KI (v) (ml)	Duration (second)	1/t	vt	V α t
10	10	5	15	1	20	20	0.05	400	0.08
10	10	5	20	1	15	23	0.043	345	0.06
10	10	5	25	1	10	32	0.031	320	0.04
10	10	5	30	1	5	46	0.022	230	0.02

                        Table 1.1