Equilibrium constants can be measured for the dissociation of Lewis acid-base complexes such as the dimethyl ether complex of BF₃, (CH₃)₂O→BF₃. The value of K (here K_p) for the reaction is 0.17 at 125 °C.

(CH₃)₂O→BF₃(g) ⇄ BF₃(g) + (CH₃)₂O(g)

1. (a) Describe each product as a Lewis acid or a Lewis base.
2. (b) If you place l.00 g of the complex in a 565-mL flask at 125°C, what is the total pressure in the flask when equilibrium is established? What are the equilibrium partial pressures of the Lewis acid, the Lewis base, and the complex?

Interpretation:

Each prduct as a lewis acid or a lewis base is to be stated.

Concept Introduction:

A Lewis acid is a substance that contains an empty orbital which is capable of accepting an electron pair. A Lewis base is a substance that has a filled orbital containing an electron pair which is not involved in bonding but may form a dative bond with a lewis acid.

A lewis acid can accept a pair of electrons from a lewis base. The boron in BF3 is electron poor and has an empty orbital, so it can accept a pair of electrons, making it as a lewis acid.

Methyl ether ((CH3)2O) is a lewis base, it can donate it’s lone pair of electrons. Chemical reaction between ((CH3)2O) and BF3, the lone pair from methyl ether will form a dative bond with the empty orbital of BF3 to form an adduct

Interpretation:

Total pressure at equilibrium, partial pressure of lewis acid and lewis base has to be calculated.

Concept Introduction:

A Lewis acid is a substance that contains an empty orbital which is capable of accepting an electron pair. A Lewis base is a substance that has a filled orbital containing an electron pair which is not involved in bonding but may form a dative bond with a lewis acid.

Ideal gas equation,

PTV=nRT (1)

Here,

PT is total pressure of the gas.

V is volume of the gas container.

n is total number of moles of gas particles.

R is gas constant.

T is temperature.