Question

Which of the following imparts purple colour to glass?
A.${\text{C}}{{\text{r}}_2}{{\text{O}}_3}$
B.${\text{AuC}}{{\text{l}}_3}$
C.${\text{C}}{{\text{u}}_2}{\text{O}}$
D.${\text{Mn}}{{\text{O}}_2}$

Answer 1

Glass is a non-crystalline, typically transparent amorphous solid with broad practical, technical, and ornamental applications in window panes, dinnerware, and optics, among other things. Glass is most commonly generated by the quick cooling (quenching) of molten metal; but, certain glasses, such as volcanic glass, occur spontaneously.

Complete answer: When thin, ordinary soda-lime glass looks colourless to the human eye, but iron oxide impurities give a green tinge that may be seen in thick pieces or with scientific instruments. Glass can be coloured with additional metals and metal oxides during the manufacturing process, which can improve its visual appeal. The following are some examples of these additives:
Glass may be tinted with iron(II) oxide to produce bluish-green glass, which is commonly used in beer bottles. It produces a deeper green hue when combined with chromium, which is used in wine bottles.
Sulfur is combined with carbon and iron salts to make iron polysulfides, which result in amber glass that ranges from yellowish to virtually black in colour. Sulfur gives borosilicate glasses with a lot of boron a blue tint. It turns a rich yellow colour when calcium is added.
Manganese can be added in tiny amounts to eliminate the green tint caused by iron, or in larger amounts to give glass an amethyst hue. Manganese is one of the earliest glass additions, with purple manganese glass dating back to ancient Egypt.
Blue glass is made from small amounts of cobalt (0.025 to 0.1 percent). When employing potash-containing glass, the best results are obtained. Decolorizing may be done with very little quantities.
To remove the green hue from the glass, black manganese dioxide ${\text{Mn}}{{\text{O}}_2}$ is employed, which is slowly transformed to sodium permanganate, a dark purple chemical. Because of this chemical alteration, certain houses built more than 300 years ago in New England contain window glass that is delicately tinged violet, and such glass panes are valued as antiques. This process is sometimes mistaken with the production of "desert amethyst glass," which occurs when glass is exposed to high-ultraviolet desert sunlight and acquires a delicate violet colour. Because it is not easy to get or create them properly, the details of the technique and the composition of the glass vary, as do the outcomes.
Hence option D is correct.

Note:
Enamelled glass, which is simply a technique for painting patterns or pictures on glass vessels and stained glass, and glass paint, often in black, and silver stain, which gives yellows to oranges on stained glass, are the main ways. When correctly applied, all of them are burned in a kiln or furnace to fix them, and they may be exceedingly durable. This is not the case with "cold-painted" glass, which is made with oil paint or other combinations and only lasts a few centuries.