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the iodine does not turn the starch black.
"The iodine clock reaction is based around the colour change that occurs when iodine reacts with starch, turning from a clear colour to a black-blue colour." (2) The starch allows the iodine and the iodide ions to bond, forming a triodide ion.
I2(aq) + I−(aq) ⇌ I3−(aq)
In this reaction, iodide is viewed as a base, and iodine is viewed as an acid.
The iodine is a ligand and is surrounded by the starch,
as for the colour change, that is due to the iodine absorbing all light wavelengths corresponding to colours, hence not letting any through, so what you are seeing when the solution is black, is the absence of light and colour alltogether,
hope that helps
Wiki User
∙ 14y ago
Wiki User
∙ 9y agoThe formation of the intense blue color formed in the iodine test for starch is a result of the formation of polyiodide chains from the reaction of starch and iodide. The straight chain portion of starch forms helices where iodine molecules assemble.
Wiki User
∙ 14y agoThe starch reacts to form polyiodide columns in a helix of amylose. Where an iodide solution and a starch solution are both clear (or at least yellow and white, respectively), this structure has a dark blue/purple colour.
Wiki User
∙ 13y agoThe iodine clock reaction is based around the colour change that occurs when iodine reacts with starch, turning from a clear colour to a black-blue colour." (2) The starch allows the iodine and the iodide ions to bond, forming a triodide ion.
I2(aq) + I−(aq) ⇌ I3−(aq)
In this reaction, iodide is viewed as a base, and iodine is viewed as an acid.
The iodine is a ligand and is surrounded by the starch,
as for the colour change, that is due to the iodine absorbing all light wavelengths corresponding to colours, hence not letting any through, so what you are seeing when the solution is black, is the absence of light and colour alltogether,
Wiki User
∙ 8y agoThe blue color is produced by a triiodide ion (I3-) that is only stable in the presence of the amylose in starch. Without amylose this ion either does not form and/or breaks up and the iodine retains its brown color.
Wiki User
∙ 12y agobecause during d reaction iodine mix with starch
Wiki User
∙ 14y agoIodine is most commonly found in a brown aqueous solution that turns purple in the presence of starch
Wiki User
∙ 11y agoBlue
Wiki User
∙ 10y agoDark Blue
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What makes iodine turn purple?
when iodine is added to a substance it turns dark blue when starch is present, and remains brown when starch is not present. This is basically because iodine forms a polypeptide complex with starch, resulting in the dark blue solution.
Why did the leaf turn blue black when iodine was added in the starch test?
because photosynthesis has occured in the leaf. starch is produced and turns iodine blue-black indicating the presence of starch.
What happens to bread when you put iodine on it?
When you pore iodine on a piece of bread, the bread will turn black. Why? Because, the iodine has a chemical reaction with the starch in the bread. This method is great to find out if a food contains starch (I suggest a potato to try next!).
What is iodine used as an indicator for?
Iodine is used as an indicator for starch. When a substance has iodine added to it, then it will turn into a dark blue color. This is a sign that the substance indeed has starch in it.
Why do green leaves turn blue black when iodine is added?
because the leaves have photosynthesized- glucose is produced. therefore, the excess glucose is converted to starch. The starch is then stored in the leaf-starch is what causes the "green" leaf to turn blue black, as iodine turns blue-black when it reacts with starch.:P
Does iodine turn blue?
Iodine turns blue in the presence of starch
What effect does iodine have on starch?
it will turn the starch into blue black colour
What makes iodine turn purple?
when iodine is added to a substance it turns dark blue when starch is present, and remains brown when starch is not present. This is basically because iodine forms a polypeptide complex with starch, resulting in the dark blue solution.
Why did the leaf turn blue black when iodine was added in the starch test?
because photosynthesis has occured in the leaf. starch is produced and turns iodine blue-black indicating the presence of starch.
What color does the indicator turn when starch is present?
Iodine is used to indicate whether starch is present in a solution. If starch IS present, the indicator will turn dark blue/black. Iodine is used to indicate whether starch is present in a solution. If starch IS present, the indicator will turn dark blue/black. FOR WHAT PURPOSE WE USE STARCH-IODINE INDICATOR PAPER
What happens to bread when you put iodine on it?
When you pore iodine on a piece of bread, the bread will turn black. Why? Because, the iodine has a chemical reaction with the starch in the bread. This method is great to find out if a food contains starch (I suggest a potato to try next!).
What is iodine used as an indicator for?
Iodine is used as an indicator for starch. When a substance has iodine added to it, then it will turn into a dark blue color. This is a sign that the substance indeed has starch in it.
What color does iodine turn when you do an experiment for starch?
dark blue - purple
What chemical is used to test for starch and what is the result if starch is present?
The chemical is called Iodine solution. If starch is present, the iodine solution will turn from amber to blue black.
What colors does starch turn if there is a little amount present?
starch will not change its own colour but it can change the colour of iodine solution. iodine solution is originally brown. after adding starch, it will turn into dark blue.
Why do green leaves turn blue black when iodine is added?
because the leaves have photosynthesized- glucose is produced. therefore, the excess glucose is converted to starch. The starch is then stored in the leaf-starch is what causes the "green" leaf to turn blue black, as iodine turns blue-black when it reacts with starch.:P
What is the chermical you test for starch?
Starch has high affinity for Iodine and in presence of iodine crystals starch turns blue from being colourless. This the fundamental that is used for chemically identifying the starch.
