This set of Class 11 Chemistry Chapter 7 Multiple Choice Questions & Answers (MCQs) focuses on “Homogeneous Equilibria”.
1. The equilibrium N2(g) + O2(g) \(\rightleftharpoons\) 2NO(g), is an example of _____________
a) homogeneous chemical equilibrium
b) heterogeneous chemical equilibrium
c) neither homogeneous nor heterogeneous
d) both homogeneous and heterogeneous
View Answer
Explanation: 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.
2. The units of KP and KC are equal.
a) true
b) false
View Answer
Explanation: 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.
3. Br2(l) \(\rightleftharpoons\) Br2(g) is in ________
a) homogeneous equilibrium
b) not in both Homogeneous and heterogeneous equilibrium
c) cannot say
d) may or may not be in Homogeneous equilibrium
View Answer
Explanation: 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.
4. Write pressure in terms of concentration and temperature.
a) P = CRT
b) P = nrt
c) p = CT
d) C = PT
View Answer
Explanation: 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.
5. At constant temperature, the pressure is directly proportional to the concentration of the gas.
a) true
b) false
View Answer
Explanation: 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.
6. For the following equation, 2HBr(g) \(\rightleftharpoons\) H2(g) + Br2(g); are both KP and KC are equal?
a) yes
b) cannot say
c) no
d) depends on the temperature
View Answer
Explanation: We have here KC = [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 KP and KC are equal.
7. What is the relation between KP and KC?
a) KC = KP
b) KC = KP(RT)
c) KC = KP(RT)Δng
d) KP = KC(RT)Δng
View Answer
Explanation: For example, take the reaction 2HBr(g) \(\leftrightarrow\) H2(g) + Br2(g), KC = [H2][Br2]/[HBr]2; KP = [pH2][pBr2]/[pHBr]2, where pH2 = [H2]RT, pBr2 = [Br2]RT and [pHBr] = [HBr]RT. So we can say that Kp = Kc(RT)Δng, where Δng = moles of products – moles of reactants which are in gaseous state only.
8. If KC of a reaction N2(g) + O2(g) \(\rightleftharpoons\) 2NO(g) is 2 x 10-3, then what is the KP?
a) 4 x 10-3
b) 1 x 10-3
c) 3 x 10-3
d) 2 x 10-3
View Answer
Explanation: As we know that KP = KC(RT)Δng, here Δng = moles of products – moles of reactants which are in gaseous state only = 2 – (1+1) = 0. So KP = KC(RT)0, KP = KC(1) = KC; KP = KC, therefore KP is same as KC and KP is 2 x 10-3.
9. CO2(g) + C(s) \(\rightleftharpoons\) 2CO(g) is an example of _____________
a) homogeneous equilibrium
b) heterogeneous equilibrium
c) neither homogeneous nor heterogeneous
d) both homogeneous and heterogeneous
View Answer
Explanation: 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.
10. WHat is the expression of KC of the chemical equation Ag2O(s) + 2HNO3(aq) \(\rightleftharpoons\) 2AgNO3(aq) +H2O(l)?
a) [AgNO3(aq)]2/[HNO3(aq)]2
b) [AgNO3(aq)]/[HNO3(aq)]2
c) [AgNO3(aq)]2/[HNO3(aq)]
d) [AgNO(aq)]2/[HNO3(aq)]2
View Answer
Explanation: 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 = [AgNO3(aq)]2/[HNO3(aq)]2.
Sanfoundry Global Education & Learning Series – Chemistry – Class 11.
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