Q7 of 73 Page 224

Explain why pure liquids and solids can be ignored while writing the equilibrium constant expression?

Concentration of solid or pure liquid,

[substance] =


=


=


Since density and molar mass doesn’t vary, concentration of the substance remains constant.


Pure liquids and solid have a constant concentration. Composition of solids remain same throughout a reaction even though amount may change.


Similarly, pure liquids have same composition (since it has only one substance)


More from this chapter

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5

Find out the value of Kc for each of the following equilibria from the value of Kp:

(i) 2NOCl (g) ⇌2NO (g) + Cl2 (g); Kp= 1.8 × 10–2 at 500 K


(ii) CaCO3 (s) ⇌CaO(s) + CO2(g); Kp= 167 at 1073 K

 6

For the following equilibrium, Kc= 6.3 × 1014 at 1000 K

NO (g) + O3 (g) ⇌NO2 (g) + O2 (g)


Both the forward and reverse reactions in the equilibrium are elementary bimolecular reactions. What is Kc, for the reverse reaction?

 8

Reaction between N2 and O2– takes place as follows:

2N2 (g) + O2 (g) ⇌2N2O (g)


If a mixture of 0.482 mol N2 and 0.933 mol of O2 is placed in a 10 L reaction vessel and allowed to form N2O at a temperature for which Kc= 2.0 × 10–37, determine the composition of equilibrium mixture.

 9

Nitric oxide reacts with Br2 and gives nitrosyl bromide as per reaction given below:

2NO (g) + Br2 (g) ⇌2NOBr (g)


When 0.087 mol of NO and 0.0437 mol of Br2 are mixed in a closed container at constant temperature, 0.0518 mol of NOBr is obtained at equilibrium. Calculate equilibrium amount of NO and Br2.