Soda-lime glass is generally softer and has a higher coefficient of thermal expansion compared to Pyrex (borosilicate) glass. Pyrex glass contains boron trioxide, which provides superior thermal shock resistance and hardness, making option C the incorrect statement.

Soda glass is composed of sodium and calcium silicates. Crown glass contains sodium, barium, zinc, and magnesium silicates. Flint glass is a mixture of potassium and lead silicates. Pyrex (borosilicate) glass contains sodium, zinc, and aluminium silicates.

In the manufacturing of Portland cement, lime (calcium oxide) is a critical component. If the proportion of lime exceeds the required stoichiometric balance, the excess free lime remains uncombined. During the hydration process, this excess lime expands, leading to internal stresses that cause the cement to crack or lose its structural soundness upon setting and hardening.

The addition of cobalt oxide (CoO) to the molten glass mixture during manufacturing results in a deep blue color. This is a classic example of using transition metal oxides as colorants in glass production. Other oxides, such as copper or iron, produce different colors like green or blue-green depending on their oxidation state and the glass composition.

Portland cement sets very quickly when mixed with water due to the presence of tricalcium aluminate. Gypsum (calcium sulfate dihydrate) is added to the clinker during grinding to act as a retarder. It slows down the hydration process, allowing sufficient time for the cement to be mixed, transported, and placed before it hardens.

Statement 1 is correct as lead glass (flint glass) is used for cut glass due to its high refractive index. Statement 3 is correct as quicklime is indeed calcium oxide (CaO). Statement 2 is technically incomplete or misleading in some contexts because while sodium carbonate is a raw material, silica (sand) is the primary component of soda glass. Given the options, C is the most accurate selection.

The industrial manufacture of soda-lime glass typically involves melting a mixture of silica sand (silicon dioxide), soda ash (sodium carbonate), and limestone (calcium carbonate). The soda ash acts as a flux to lower the melting point of the silica, while the limestone is added to improve the chemical durability and water resistance of the final glass product.

Glass is often described as a supercooled liquid because it is an amorphous solid that lacks a long-range crystalline structure. When molten glass is cooled rapidly, it does not undergo a phase transition into a crystalline solid but instead becomes increasingly viscous until it reaches a rigid, glass-like state. This state retains the disordered molecular arrangement characteristic of a liquid.

Source answer preserved: option B ($$CaS{O_4} \cdot 2{H_2}O$$). AI attempted to change protected answer data (option_b, option_d), so this item is flagged for manual review before study use.

Pyrex is a type of borosilicate glass. Borax (sodium borate) is a key ingredient used in its manufacture. The addition of boron oxide (derived from borax) to the silica glass matrix significantly reduces the coefficient of thermal expansion, making the glass highly resistant to thermal shock and chemical corrosion.