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Why potassium thiocyanate is added in the titration of sodium thiosulphate with copper?
Wiki User
∙ 15y ago
On addition of the KI to your copper (II) solution, you formed Copper (I) iodine solid and produced the tri-iodide ion. It is the tri-iodide ion that you are titrating with the sodium thiosulfate. The tri-iodine ion is what itercalates into the starch molecules to form the dark blue color you are using as an end point in the titration. Some the the tri-iodide ion formed will adsorb to the surface of the solid copper (I) iodine formed. This must be desorbed for a complete titration. The addition of the potassium thiocyanate, displaces the adsorbed tri-iodine ion, and liberates it for titration.
Wiki User
∙ 15y ago
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In estimation of copper and nickel why we are using volumetric for copper and gravimetric for nickel seperately?
It is simply because they could not be found together!! copper can be estimated by treating with potassium iodide and iodine will be liberated in the reaction which is titrated against sodium thiosulphate during the reaction we will add sulphuric acid to prevent the hydrolysis of copper sulphate and we follow by, adding ammonia to neutralize sulphuric as it may hinder the reation between iodide and copper!! now again we will add acetic acid to neutralize ammonia.. and the indicator is added at the last because it will get absorbed with the iodine!! now atlast we add ammonium, thiocyanate to prevent the excess of iodine getting added to copper iodide. end point is disappearance of blue color.
What is the usage of KCNS in a iodometric titration?
Some of the metal ion that is estimated (especially Cu2+) may get trapped within starch indicator. When KCNS is added, copper thiocyanate or Cu(CNS)2 complex is formed which then reacts with the KI added, giving correct results.
Explain about Condutometric titration's of copper sulphate with sodium hydroxide?
how the end point is determined
What colour is copper iodide and potassium sulphate?
Potassium sulfate would be colorless; copper iodide is probably blue or green (I don't know which off the top of my head, but copper salts are generally either blue or green).
What is the difference between anhydrous sodium thiosulphate and sodium thiosulphate?
None. Anhydrous simply means ..... (not in solution). The opposite is aqueous (in solution).Added:..... crystalised without hydrate in the solid crystals.mono-hydrate means it is crystallised with 1 (one) molecule H2O per molecule salt.CuSO4.5H2O means : penta-hydrate of copper sulfate
What is produced when Copper nitrate and potassium thiocyanate react?
copper (thiocyanate)2 and potassium nitrate
Why is KSCN used in iodometry of copper?
On addition of the KI to your copper (II) solution, you formed Copper (I) iodine solid and produced the tri-iodide ion. It is the tri-iodide ion that you are titrating with the sodium thiosulfate. The tri-iodine ion is what itercalates into the starch molecules to form the dark blue color you are using as an end point in the titration. Some the the tri-iodide ion formed will adsorb to the surface of the solid copper (I) iodine formed. This must be desorbed for a complete titration. The addition of the potassium thiocyanate, displaces the adsorbed tri-iodine ion, and liberates it for titration.
Why potassium thiocyanate is added in redox iodometric titration of copper sulphate?
Cu2I2 is precipitates in light pink colour due to adsorption of I2 and the precipitate releases I2 very slowly. Therefore very small amount of potassium thiocyanate is added towards the end point which helps to displace the adsorbed I2 quickly by combining with Cu2I2 to form CuSCN which has less tendency to adsorb I2.
What is the formula for copper ii thiocyanate?
Cu2CuN2S2
In estimation of copper and nickel why we are using volumetric for copper and gravimetric for nickel seperately?
It is simply because they could not be found together!! copper can be estimated by treating with potassium iodide and iodine will be liberated in the reaction which is titrated against sodium thiosulphate during the reaction we will add sulphuric acid to prevent the hydrolysis of copper sulphate and we follow by, adding ammonia to neutralize sulphuric as it may hinder the reation between iodide and copper!! now again we will add acetic acid to neutralize ammonia.. and the indicator is added at the last because it will get absorbed with the iodine!! now atlast we add ammonium, thiocyanate to prevent the excess of iodine getting added to copper iodide. end point is disappearance of blue color.
What is the usage of KCNS in a iodometric titration?
Some of the metal ion that is estimated (especially Cu2+) may get trapped within starch indicator. When KCNS is added, copper thiocyanate or Cu(CNS)2 complex is formed which then reacts with the KI added, giving correct results.
What is copper carbonate plus potassium?
Potassium Carbonate and Copper metal
The differences in the reactions of potassium magnesium and copper with water?
the diffrences in reaction of potassium, magnesium and copper
What is Benedict solutions?
Benedict's solution, or Benedict's reagent, is a solution used for the analysis of reducing sugars. It may be qualitative or quantitave. The former is composed of copper sulphate, sodium carbonate and sodium citrate while the later additionally contains potassium ferrocyanide and potassium thiocyanate. The solution is so named after Stanley Rossiter Benedict, the scientist who created it.
what is the balanced equation for copper(II)oxide and potassium chloride?
The balanced equation for copper(II) oxide and potassium chloride is CuO + 2KCl → CuCl2 + K2O When copper(II) oxide reacts with potassium chloride then it forms copper(II) chloride and potassium oxide.
What happens when copper metal reacts with potassium cyanide?
Copper metal is less reactive than potassium so it will not react with potassium cyanide.
Explain about Condutometric titration's of copper sulphate with sodium hydroxide?
how the end point is determined
