Chapter 7 Equilibrium Solutions
Question - 31 : - Dihydrogen gas used in Haber’s process isproduced by reacting methane from natural gas with high temperature steam. Thefirst stage of two stage reaction involves the formation of CO and H2. In second stage, COformed in first stage is reacted with more steam in water gas shift reaction,
If a reaction vessel at 400°C is charged with anequimolar mixture of CO and steam such that 
4.0 bar, what will be the partial pressureof H2 at equilibrium? Kp= 10.1at 400°C
Answer - 31 : -
Let the partial pressure of both carbondioxide and hydrogen gas be p. The given reaction is:
It is 
Now,
Hence,at equilibrium, the partial pressure of H2 will be 3.04 bar.
Question - 32 : - Predictwhich of the following reaction will have appreciable concentration ofreactants and products:
a) 
b) 
c) 
Answer - 32 : -
Ifthe value of Kc lies between 10–3 and 103, a reaction hasappreciable concentration of reactants and products. Thus, the reaction givenin (c) will have appreciable concentration of reactants and products.
Question - 33 : - The value of Kc for the reaction
3O2 (g) 
2O3 (g)
is 2.0 ×10–50 at 25°C. If theequilibrium concentration of O2 in air at 25°C is1.6 ×10–2, what is the concentration of O3?
Answer - 33 : -
Thegiven reaction is:
Then,we have,
Hence, the concentration of
Question - 34 : - The reaction, CO(g) + 3H2(g)
CH4(g) + H2O(g) is at equilibrium at1300 K in a 1L flask. It also contain 0.30 mol of CO, 0.10 mol of H2 and 0.02 mol of H2O and an unknown amount ofCH4 in the flask. Determine theconcentration of CH4 in the mixture. The equilibriumconstant, Kc for the reaction at the giventemperature is 3.90.
Answer - 34 : -
Let the concentration of methane atequilibrium be x.
It is given that Kc = 3.90.
Therefore,
Hence,the concentration of CH4 at equilibrium is 5.85 × 10–2 M.
Question - 35 : - Whatis meant by the conjugate acid-base pair? Find the conjugate acid/base for thefollowing species:
Answer - 35 : -
Aconjugate acid-base pair is a pair that differs only by one proton.
Theconjugate acid-base for the given species is mentioned in the table below.
| Species | Conjugate acid-base |
| HNO2 | 
|
| CN– | HCN (acid) |
| HClO4 | 
|
| F– | HF (acid) |
| OH– | H2O (acid) /O2– (base) |
| 
| 
|
| S2– | HS– (acid) |
Question - 36 : - Which of the followings are Lewis acids? H2O, BF3, H+, and
Answer - 36 : - Lewis acids are those acids which can accept apair of electrons. For example, BF3, H+, and 
are Lewis acids.
Question - 37 : - What will be the conjugate bases for theBrönsted acids: HF, H2SO4 and HCO3?
Answer - 37 : -
Thetable below lists the conjugate bases for the given Bronsted acids.
| Bronsted acid | Conjugate base |
| HF | F– |
| H2SO4 | 
|
| 
|
|
Question - 38 : - Write the conjugate acids for the followingBrönsted bases: NH2–, NH3 and HCOO–.
Answer - 38 : -
Thetable below lists the conjugate acids for the given Bronsted bases.
| Bronsted base | Conjugate acid |
| 
| NH3 |
| NH3 | 
|
| HCOO– | HCOOH |
Question - 39 : - The species: H2O,
, and NH3 can act both asBrönsted acids and bases. For each case give the corresponding conjugate acidand base.
Answer - 39 : -
Thetable below lists the conjugate acids and conjugate bases for the givenspecies.
| Species | Conjugate acid | Conjugate base |
| H2O | H3O+ | OH– |
|
| H2CO3 |
|
|
| H2SO4 |
|
| NH3 |
|
|
Question - 40 : - Classify the following species into Lewisacids and Lewis bases and show how these act as Lewis acid/base: (a) OH– (b) F– (c) H+ (d) BCl3.
Answer - 40 : -
(a) OH– is a Lewis basesince it can donate its lone pair of electrons.
(b) F– is a Lewis basesince it can donate a pair of electrons.
(c) H+ is a Lewis acidsince it can accept a pair of electrons.
(d) BCl3 is a Lewis acidsince it can accept a pair of electrons.