why does silica gel when dissolved in water gives pink colouration??
821859
Silica gel is white. Silica gel is insoluble in water.
1005699
The same thing that causes prizms in crystals.  It is the colors of light, the rain condenses them just as the crystal does
970198
Solutions of some chemicals are coloured because the molecules in the solution selectively absorb certain colours from the light passing through. For example, if the chemical absorbed red light then the solution would appear blue-green. In the case of potassium permanganate almost all colours are absorbed, leaving only the blue/indigo/violet range (to use the popular names for the rainbow colours) to get through and cause the purple colour.\n\nNot sure by "band" whether you mean absorption band or transmittance band but the mechanism to produce one would be almost the same. An absorption band is caused by a strong removal of a certain colour (or range of wavelengths) in the area of the band and a transmittance band by the strong removal of colours on each side of the band.\n\nColours are absorbed because the energy the photons having that particular wavelength contain is exactly enough to excite an electron within a molecule. This excitation raises the electron to a higher energy level and the photon is absorbed. Somewhat later, the energy is returned to the system as the electron returns to its former energy level (often via other intermediate levels). The energy is not usually returned as light again however, but more often as a form of heat (a vibration of the crystal lattice, actually). In those cases where the energy does reappear as light the phenomenon is called luminescence, or in some circumstances laser action.\n\nElectrons associated with atoms in molecules and/or complex crystal lattices can have their energy levels changed by the close association with other atoms and so make it more likely they will absorb visible light. This is one of the reasons there are many more coloured compounds than elements. In particular, certain minerals can develop intensely absorbing locations within their structure called "colour centres" which is what produces the deep colours of precious stones. Diamond, on the other hand, is transparent because its highly ordered and stable structure means that a photon would need to have quite a high energy for it to be absorbed and so all visible light passes through unchanged.\n\nHope this is what you were after.
814399
Pure silica sand will be unaffected by hydrogen peroxide. Salt (NaCl) will be dissolved in the H2O2-solution.\n\nIf you take sand from the garden or similar sources, the sand will have impurities (bacteria, decomposed organic matter, up to short fragments of roots) which will react with the H2O2 - large particles will be bleached, smaller ones will be oxidized and dissolved. H2O2-solution is used to free sediment samples of organic "glues" which prevent sieving. Depending on the degree of organic contamination, concentrations between 5 and 25% are used. Too strong solutions meeting lots of organic material will heat up, foam up and create a mess that can bleach skin and attack surfaces and organs (eyes, other tissue). Thinning with cold water usually slows down the foaming.
631362
It's the die in the soda mixed with what is normally brown stool.  It's weird, but you can get the same result with mixing water colors together.
897445
usually for gram stain, if the color is blue, the organism is gram positive and if it's pink, the organism is gram negative since the cell wall structure wouldn't be able to sustain the washing; however, the result would only be valid for a short amount of time....and since the culture was left in the incubator for a longer period of time, some of the same microorganisms have lost the ability to retain the stain and therefore the color changed from intense blue to pink...the best thing to do would be to redo the gram stain and to make sure that the culture does not stay in the incubator for too long
728020
any solution gives colour due to the fact that the outermost electrons absorb the energy and move to a highre orbit corrospondingly. when they come back to their orignal state, the enegry is emitted in the form of photons, which may have the wavelength crrspndngly to a colour.
675989
If when you mix the two together the solution turns clear, you have a solution.  If it makes a cloudy mixture, or if there is visible solid on the bottom, you have a heterogeneous mixture, or a non-uniform mixture, which is not a solution.
348053
where are you from?? it turns pink here... any ways its the phosphorus in the clouds.
1058175
Flowers which change color often do so based upon the acid or base content of the soil.\n\nThis might be the situation in your case.
360273
Silica gel is used to absorb water from a gaseous environment the water absorbing capacity is usually around 25% by weight, \n\nso it absorbs the water in human body causes dehydration
380887
lol, last minute lab write ups. afaik enzymes dont change colour, as they are not supposed to change so id bet there is something else that the enzyme works on. better put up the other reagents to get a better answer
1114354
It's a mineral. Magnesium Silicate Hydroxide.
646111
You can turn it black with an iodine solution, then turn it back with sodium thiosulphate solution. Neat trick.
344786
color is a phenomenon when the dye in the clothes absorbes light, the molecule becomes excited to a higher energy level, back to ground state, and a different color light is emmitted. \n\nI'm thinking since the color just looks "darker" without any change in the spectrum. that means you only get a decrease in intensity (fewer photons). so water may have a quenching effect for the flourescence of the dye when it's close to the dye molecule. that way many emmitted photon is quickly quenched by the water molecule and fewer are allowed to escape and be seen so the color looks darker.
638188
I assume you are titrating against a standard mixture, now in Na2S2O3 the solution will contain Na+ ions which are colourless. However Cu+ and Cu2+ ions which occur in the 2nd case are prone to atmospheric oxidation producing a film of CuO or Cu(OH)2, thus the cloudy appearance.
874373
funny question\n\nccl4 is insoluble in water since it cannot form hydrogen bond with water\nsicl4 is soluble in water since it hydrolyse in water to give SiO2\nand HCl