Option 1: The statement that "glass is often said to be a supercooled liquid" is correct. Glass does not have a crystalline structure like most solids, but it instead has an amorphous or disordered structure. This gives it some liquid-like properties, and it is often referred to as a supercooled liquid.

Option 2: The statement that "glass has no definite melting point" is correct. Unlike most solids, which have a specific temperature at which they melt, glass does not have a sharp melting point. Instead, it gradually softens and becomes more viscous as it is heated.

Option 3: The statement that "soda glass is harder than Pyrex glass" is incorrect. Soda glass is actually softer than Pyrex glass. Soda glass is a type of glass made primarily from sodium carbonate, while Pyrex is a type of glass that contains boron. Pyrex glass is known for its higher thermal resistance and durability compared to soda glass.

Option 4: The statement that "boron is present in Pyrex glass" is correct. Boron is indeed present in Pyrex glass, and it contributes to its thermal resistance and durability. The addition of boron gives Pyrex glass a lower coefficient of thermal expansion,