Question

Give reasons:
A. Why does boron trifluoride behave as Lewis acid?
B. $C{O_2}$ is a gas, while $Si{O_2}$ is a solid at room temperature

Answer 1

The inorganic compound $B{F_3}$stands for boron trifluoride. In moist air, this pungent, colourless poisonous gas produces white gases. It's a useful Lewis acid and a flexible boron compound building stone. The term "electron deficient" is also used to describe $B{F_3}$, which is supported by its exothermic reactivity against Lewis bases.

Complete answer:
Any substance that can accept a pair of nonbonding electrons, such as the H⁺ ion, is referred to as a Lewis acid. A Lewis acid, in other words, is an electron-pair acceptor. A Lewis base is any element that can donate a pair of nonbonding electrons, such as the OH⁻ ion. As a result, a Lewis base is an electron-pair donor.
Since it is an electron-deficient species that can accept electron pairs, boron trifluoride BF₃ behaves as a Lewis acid. We can see that the Boron structure is $1{s^2}2{s^2}2{p^1}$ and that an empty p-orbital exists, indicating that mean $B{F_3}$ has a propensity to embrace a lone pair, indicating that BF is Lewis acid.
Because of what are known as "van der Waals forces" or "London forces," each molecule in CO₂ is drawn to other molecules. Van der Waals forces are a weak form of intermolecular force that attracts transient and induced dipoles. Carbon dioxide melts at just over -56.6 degrees Celsius and Van der Waals forces can be broken with no energy.
Per silicon atom in $Si{O_2}$ is covalently bound to four oxygen atoms. An oxygen atom has two silicon atoms bound to it. This results in a massive tetrahedral arrangement, similar to that of a diamond. The lattice is very strong and all of the atoms are bound by covalent bonds. The melting point of $Si{O_2}$is 1713 °C, demonstrating this.
Hence it is a solid in room temperature.

Note:
Silicon dioxide, also known as silica, is a silicon oxide with the chemical formula $Si{O_2}$. It is most often found as quartz in nature and in various living species. Silica is a significant component of sand in many parts of the world.