Test: Homogeneous Equilibria - Chemistry MCQ

The units of KP are (atm)Δng and the units of KC are (mol/L)Δng. Where Δng = moles of products – moles of reactants which are in the gaseous state only. As the units of KP and KC are not equal the above statement is considered to be false.

We all know that the ideal gas equation is PV = nRT; P = nRT/V; P = CRT here N/v is concentration, P is the pressure, V is the volume, n is the number of moles, C is the concentration, R is the universal gas constant and T is the temperature.

We have here K_C = [H₂][Br₂]/[HBr]²; KP = [pH₂][pBr₂]/[pHBr]², where pH₂ = [H₂]RT, pBr₂ = [Br₂]RT and [pHBr] = [HBr]RT. So in this case as Δng = 0, where Δng = moles of products – moles of reactants which are in gaseous state only, both K_P and K_C are equal.

As we know that K_C = K_P(RT)^Δng, here Δng = moles of products – moles of reactants which are in gaseous state only = 2 – (1+1) = 0. So K_C = K_P(RT)0, KC = K_P(1) = K_P; K_C = K_P, therefore K_P is same as K_C and K_P is 2 x 10^-3.

It is important that for the existence of heterogeneous equilibrium pure solid or liquid must also be at equilibrium, but their concentrations do not appear in the expression of the equilibrium constant. So here KC = [AgNO_3(aq)]²/[HNO_3(aq)]²

In homogeneous equilibrium, the reactants and products are present in the same phase or physical state. Nitrogen, Oxygen, and nitrogen monoxide are present in a gaseous state, so it is homogeneous chemical equilibrium.

As we know that in Homogeneous equilibrium the reactants and products are present in the same phase or physical state but here it is in a liquid state and gaseous state, so it is not in Homogeneous equilibrium.

We have P = CRT e where p is pressure, R is a universal constant and T is the temperature, we derive the equation from the ideal gas equation PV=nRT. So from P = CRT, we can say that at a constant temperature the pressure is directly proportional to the concentration of the gas.

The relation between K_P and K_C is that K_P is the rate constant of a chemical reaction and K_C is the equilibrium constant of the reaction. The relationship between K_P and K_C can be expressed as K_P = K_C(RT)^Δng, where R is the ideal gas constant, T is the temperature in Kelvin, and Δng is the difference in the number of moles of gas between the product and reactant states.

In heterogeneous equilibrium, the reactants and products are present in two or more physical States or phases. Here carbon dioxide is present in the gaseous state while carbon is present in the solid state, so it is an example of heterogeneous equilibrium.