Iodine Thiosulfatetitrations
usedtodetermine the concentration iodate ions hydrogeide
of an oxidising agent
Method
1 knownvolume 25cm a son the oxidising agent is placed
in a conical flash of of
2 Mixture is acidified using an excessof sulfuricacid
3 Solidexcess potassiumiodide is added
4Jodine in soln in the conicalflask istitratedwith standard sodiumthiosulfatesoln
Colowless brown strawyellow blueblack colourless
at
105
Tseimma mom
thiosulfateions
mom
starchindicator titratifinished
Oxidising qfg.fi etp reactagh added blueblack all iodineusedup
y Meansiodine present
Todate v ions
2oz
reduction S at
2 83
5
ant we 0 Ii brezo reduced
I oxidation
11 Is Lé oxidised
man
EE n iis s
Iodine in boththeseequs
Hydrogenperoxide are titrated withsodium
thiosulfatesoln Nay5203 52032
4202 reduction H202 2Mt 25 2420
22 25205 25 54062
2 oxidation 21 Is 2é
Overall 4202 22 2H 2H20 Iz
, Examples
1.2g ofan impuresampleof potassiumiodate V KIOS istobeanalysedforpercentage
purity A 250cm solnofsample was prepared in a volumetricflash
Describe how the250cm soln iodate v wasprepared
ofpotassium
Weigh1.2g
of sample
Dissolve in minvolume DI water withstirringrod
Transfer to a volumetric
of
flash
include rinsings
make volumeto250cm using
up DI water
Ensure bottom minisons on the line
of
Stopper I invertflash
Write theeqn the ran between potassiumiodate v iodide in
the presence for
potassium
dilute sulfuricacid
of
KI03 342504 5K 372 3H20 3kg504
Writetheionicegn
for this an
205 6Mt 57 37 3420
Iodine reactswithsodiumthiosulfate accordingtothe
eqn Fromearlierin Q
potassiumiodate
32 25203 54062 22_ Solnof
sulfurifid
4 10cm dilute
potassiumiodide
of k203 in sample
Calculatethemass the
1g 3
Or mar sodimsukn
25205 26.6averagetime
in gun
252052 72
0.00266 0.00133
itstin'sson
205 6Mt 5 3322 3420 703
j 0.00443
14
34 403
011
m
0.00133 0 000443 in 25cm
usedtodetermine the concentration iodate ions hydrogeide
of an oxidising agent
Method
1 knownvolume 25cm a son the oxidising agent is placed
in a conical flash of of
2 Mixture is acidified using an excessof sulfuricacid
3 Solidexcess potassiumiodide is added
4Jodine in soln in the conicalflask istitratedwith standard sodiumthiosulfatesoln
Colowless brown strawyellow blueblack colourless
at
105
Tseimma mom
thiosulfateions
mom
starchindicator titratifinished
Oxidising qfg.fi etp reactagh added blueblack all iodineusedup
y Meansiodine present
Todate v ions
2oz
reduction S at
2 83
5
ant we 0 Ii brezo reduced
I oxidation
11 Is Lé oxidised
man
EE n iis s
Iodine in boththeseequs
Hydrogenperoxide are titrated withsodium
thiosulfatesoln Nay5203 52032
4202 reduction H202 2Mt 25 2420
22 25205 25 54062
2 oxidation 21 Is 2é
Overall 4202 22 2H 2H20 Iz
, Examples
1.2g ofan impuresampleof potassiumiodate V KIOS istobeanalysedforpercentage
purity A 250cm solnofsample was prepared in a volumetricflash
Describe how the250cm soln iodate v wasprepared
ofpotassium
Weigh1.2g
of sample
Dissolve in minvolume DI water withstirringrod
Transfer to a volumetric
of
flash
include rinsings
make volumeto250cm using
up DI water
Ensure bottom minisons on the line
of
Stopper I invertflash
Write theeqn the ran between potassiumiodate v iodide in
the presence for
potassium
dilute sulfuricacid
of
KI03 342504 5K 372 3H20 3kg504
Writetheionicegn
for this an
205 6Mt 57 37 3420
Iodine reactswithsodiumthiosulfate accordingtothe
eqn Fromearlierin Q
potassiumiodate
32 25203 54062 22_ Solnof
sulfurifid
4 10cm dilute
potassiumiodide
of k203 in sample
Calculatethemass the
1g 3
Or mar sodimsukn
25205 26.6averagetime
in gun
252052 72
0.00266 0.00133
itstin'sson
205 6Mt 5 3322 3420 703
j 0.00443
14
34 403
011
m
0.00133 0 000443 in 25cm
