what is Unsulphonated Aromatic Amine and what are the hazards that may affect from this colour impurities?
443305
The simplest aromatic amine is called aniline. This compound is benzene (aromatic -C6H5) with an amine (-NH2). Unsulfonated means no -SO3H are on the benzene ring. I don't know about the toxicity of this compound without more specifics such as source of the color or structure of the impurity. Good luck.
1079987
No safe way to do it.  Distillation perhaps, but that's not safe as sulphate fumes are not that good for you.  \n\nGrab the stock bottle and make up a fresh solution.
422913
It is highly conjugated (lots of alternating double bonds).  These compounds tend to be colored.  They can often turn bright red when deprotonated.  This compound doesn't have an acidic proton, so you can't deprotonate it, at least not very easilly.
1056091
This a solution that may be impure because of the possibility of contamination. it is a term in chemistry and in poison control oh public health
639328
(NH4)2S.  Cu2S is dark in color.
442371
try this site.  if you ever need to look up other chemicals, etc. search for msds b/c that is where all the info on storage, etc will be.\n\nhttp://www.chem.tamu.edu/class/majors/msdsfiles/msdsleadsulfate.htm
980729
Barium Sulfate — BaSO4. It is extremely insoluble in water and will form a white precipate.
153409
What specifically are you talking about, because I've never observed such a phenomenon.  I spent a year and a half working with sulfur dioxide and debugging a device designed to create it, and I've seen how it bleaches, and I don't know of any reversion to an "unbleached" state as you mention.\n\nReduction is NOT the removal of oxygen, and sulfur dioxide doesn't reduce anything.  Sulfur dioxide is an oxidizer.  Oxidation is the process by which electrons are removed from a reducer.  Generally, the way that this destroys color is by breaking the conjugated bonds in organic molecules that absorb color.\n\nIn some cases, color can be the result of the oxidation state of a metalic atom.  In an ionic state, it might have color, while it might become colorless when it is reduced.  Oxygen in the atmosphere could certainly make a metal atom become colorful (it turns copper green, iron red, etc).  But I can't see how sulfur dioxide could function as a reducing agent.
776343
The answer is A), dimethyl amine.  B&C are primary amines while D is a tertiary amine.  A primary amine has two hydrogens attached to the nitrogen, a secondary amine has one hydrogen while a tertiary amine has none.  Note, however, that the nitrogen still always has three of something attached if it is an amine.  The organic part is often designated as "R" and/or "R' ".  So, dimethyl amine can be thought of as R2NH, where R=CH3.  This is kind of trivial in this case so it is more often used where R is a longer chain carbon compound.\n\nYou'd probably find the "R" designation used more for industrial chemicals rather than in an organic chemisty class.
339176
The result is Ag2S: Ag+ is monovalent, S2- is the sulphide ion.\n\nA solid silver surface will blacken (slowly) when exposed to material containing bound (negatively charged) sulphur atoms (such as the amino acid cystein and proteins containing it). Dissolved silver will precipitate.
450615
Any of the heavy metals, or benzene products would be excellent topics. If you attempt to present a case on a chemical that's too obscure you'll have a difficult time finding enough research/clinical trials to support your claim. Peruse the EPA website to get some other ideas.
264902
It could simply mean using dyes that are not in the azo class of dyes.  That would include phthalocyanines and formazans for examnple.
42811
http://www.uni-regensburg.de/Fakultaeten/nat_Fak_IV/Organische_Chemie/Didaktik/Keusch/D-Dyeing_vat-e.htm\n\nFound by simple web search
977460
Fe(NH4)2(SO4)2 .6H2O is highly insoluble in non polar organic solvents like chloroform, dichloromethane, etc. Might be slightly soluble in alcohols. Better you dissolve it in minimum amount of water (make highly saturated solution) and add drop by drop alcohol  in a period of time and keep aside without shaking. Crystals will grow slowly.\nIt might be helpful.
269689
Hope this helps:\n\nhttp://jchemed.chem.wisc.edu/Journal/Issues/1997/Feb/abs210.html
85803
Dyestuffs, any of a large group of chemicals almost exclusively organic in nature, used for the colouring of textiles, inks, food products, and other substances. Modern industrial terminology defines a dyestuff as a product containing pure organic dye and cutting agents or fillers that make the product easier to handle. Dyes are not to be confused with pigments, which are pulverized coloured substances that must be mixed with adhesive binding agents before being applied to surfaces. See Dyeing.\n\nThe colour properties of organic compounds depend on their structure. In general, the coloured compounds used as dyes are unsaturated organic chemicals. The quality of possessing colour is particularly noticeable in compounds containing certain well-defined chemically unsaturated groupings. These groups, known as chromophores (colour bearers), are not all equally effective in producing colour.\n\nDyestuffs must be capable of entering and colouring textile fibres or other substances. Chemical radicals, known as auxochromes, have the property of anchoring the desired dye effectively. They are acidic or basic and give rise to acidic or basic dye salts. In the case of some compounds the addition of an auxochrome group also changes a colourless compound into a coloured one.\n\nThe basic raw materials of synthetic dyes are compounds, such as benzene, that are derived from the destructive distillation of coal (see Phenylamine; Coal Tar). For this reason synthetic dyestuffs are often popularly known as coal-tar dyes. From the basic materials, intermediates are manufactured by a number of chemical processes that, in general, involve the substitution of specific elements or chemical radicals for one or more of the hydrogen atoms in the basic substance.\n\nDyestuffs can be classified according to their use or by their chemical structure. The chemical classification is generally made according to the nucleus of the compound. Among the more important dye groups are the azo dyes, which include butter yellow and Congo red; the triphenylmethane dyes, which include magenta and methyl violet; the phthalein dyes; the azine dyes, which include mauve; and the anthraquinone dyes, which include alizarin. Indigo is a vat dye, occurring in nature in the crystalline glucoside indican. An important new group of dyes is the phthalocyanine dyes, which are blue or green in colour and resemble chlorophyll in chemical structure. Of all the groups of dyes the azo dyes are the most generally useful and widely employed. See Diazo Compounds.\n\nA stain is a chemical dye or pigment used to colour glass, paper, textiles, or wood. The staining substance, which uses alcohol, oil, or water as a vehicle, is transparent and thinner than paint or coating, and it penetrates into the grain of material being dyed. In microscopic and microchemical research, a dye or a chemical mixture used to distinguish between minute transparent structures is also called a stain.\n\nx
440553
Because you mention Rf values, I assume you're asking specifically about Thin-Layer Chromatography.  Actually the molecular weight is a fairly minor factor in the Rf value.  Intermolecular interactions between the pigment in question and the solid phase and the mobile phase are the most important.  So it really comes down to the selection of the mobile phase, how polar, how acidic or basic in relation to the analyte (your pigment in this case).  pH of the mobile phase is critically important in that your pigment may ionize to a greater or lesser extent depending upon the pH, and this drastically changes the intermolecular interactions.  Stationary phase selection is also important.