Question

How can coloured glass be obtained from molten glass? Name the chemical compounds to be added to molten glass to obtain the yellow coloured glass.

Answer 1

Hint : There are various methods for colouring and colour marking glass. Colour ions are added, and nanometer-sized colloids are precipitated. Coloured inclusions (as in milk and smoked glass), light scattering (as in phase separated glass), dichroic coatings (see dichroic glass), or colourful coatings

Complete Step By Step 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. To make coloured glass from molten glass, specific metal compounds must be added to the molten glass.
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.
Hence Sulphur is the correct answer.

Note :
Chromium is a potent colourant that produces a dark green or even black colour at high doses. It produces emerald green glass when combined with tin oxide and arsenic. Glass with added chromium oxide in amounts beyond its solubility limit in glass is used to make chromium aventurine, which has aventurescence created through the formation of massive parallel chromium(III) oxide plates during cooling.