Chapter 6

Baking soda, \(\mathrm{NaHCO}_{3}\), decomposes as \(2 \mathrm{NaHCO}_{3}(\mathrm{~s}) \rightleftharpoons \mathrm{Na}_{2} \mathrm{CO}_{3}(\mathrm{~s})+\mathrm{CO}_{2}(\mathrm{~g})+\mathrm{H}_{2} \mathrm{O}(\mathrm{g})\). The equilibrium pressure is \(1.04 \mathrm{~atm}\). The \(K_{p}\) for the reaction is (a) \(0.2704\) (b) \(2.704\) (c) \(27.04\) (d) \(270.4\)

Phosphorous pentachloride dissociates as follows $$ \mathrm{PCl}_{5}(\mathrm{~g}) \text { ? } \mathrm{PCl}_{3}(\mathrm{~g})+\mathrm{Cl}_{2}(\mathrm{~g}) $$ If total pressure at equilibrium is \(P\) and the degree of dissociation of \(\mathrm{PCl}_{5}\) is \(x\), the partial pressure of \(\mathrm{PCl}_{3}\) will be (a) \(\left(\frac{x}{x+1}\right) P\) (b) \(\left(\frac{2 x}{1-x}\right) P\) (c) \(\left(\frac{x}{x-1}\right) P\) (d) \(\left(\frac{x}{1-x}\right) P\)

The effect of a catalyst to a chemical equilibrium is that it (a) lowers the activation energy of both the reactants and the products (b) inereases the activation energy of both the reactants and the products (c) lowers the activation energy of the reactants (d) lowers the activation energy of the products

At a certain temperature, \(K_{C}\) is 16 for the reaction \(\mathrm{SO}_{2}(\mathrm{~g})+\mathrm{NO}_{2}(\mathrm{~g}) \rightarrow \mathrm{SO}_{3}(\mathrm{~g})+\mathrm{NO}(\mathrm{g})\). If we take 1 mol of each of the four gases in a 11 container, what would be the equilibrium concentrations of NO and \(\mathrm{NO}_{2} ?\) (a) \(1.6,0.4\) (b) \(0.4,1.6\) (c) \(1.6,0.8\) (d) \(0.8,1.6\)

Which one of the following at equilibrium, with all reactants and products in the gaseous phase is unaffected by an increase in pressure? (a) \(\mathrm{PCl}_{5}=\mathrm{PCl}_{3}+\mathrm{Cl}_{2}\) (b) \(2 \mathrm{O}_{3} \rightleftharpoons 3 \mathrm{O}_{2}\) (c) \(\mathrm{H}_{2}+\mathrm{I}_{2} \rightleftharpoons 2 \mathrm{HI}\) (d) \(\mathrm{N}_{2} \mathrm{O}_{4} \rightleftharpoons 2 \mathrm{NO}_{3}\)

The vapour density of \(\mathrm{PCl}_{5}\) is \(104.16\) but when heated to \(230^{\circ}\) vapour density is reduced to 62. The degree of dissociation of \(\mathrm{PCl}_{5}\) at this temperature will be (a) \(6.8 \%\) (b) \(68 \%\) (c) \(46 \%\) (d) \(64 \%\)

Which of the following gaseous reactions would be favoured by reducing the pressure (a) \(\mathrm{PCl}_{5} \Rightarrow \mathrm{PCl}_{3}+\mathrm{Cl}_{2}\) (b) \(2 \mathrm{SO}_{2}+\mathrm{O}_{2} \rightleftharpoons 2 \mathrm{SO}_{3}\) (c) \(\mathrm{PCl}_{3}+\mathrm{Cl}_{2}=\mathrm{PCl}_{3}\) (d) \(\mathrm{H}_{2}+\mathrm{I}_{2} \rightleftharpoons 2 \mathrm{HI}\)

In the manufacture of ammonia by haber's process \(\mathrm{N}_{2}(\mathrm{~g})+3 \mathrm{H}_{3}(\mathrm{~g}) \neq 2 \mathrm{NH}_{3}(\mathrm{~g})+92.3 \mathrm{~kJ}\) Which of the following conditions is favourable? (a) increasing the amount of \(\mathrm{NH}_{3}\) (b) increasing the temperature (c) reducing the temperature (d) removing nitrogen

For the endothermic reaction \(\mathrm{N}_{2}(\mathrm{~g})+\mathrm{O}_{2}(\mathrm{~g})=2 \mathrm{NO}(\mathrm{g})\) Which one of the following statements is true? (a) \(K\) is independent of temperature (b) \(K\) increases as temperature increases (c) \(K\) decreases as temperature increases (d) \(K\) varies with the addition of \(\mathrm{NO}\)

The oxidation of \(\mathrm{SO}_{2}\) by \(\mathrm{O}_{2}\) to \(\mathrm{SO}_{3}\) is an exothermic reaction. The yield of \(\mathrm{SO}_{3}\) will \(\mathrm{w}\) maximum if (a) temperature is increased and pressure is kept constant (b) temperature is reduced and pressure is increased (c) both temperature and pressure are increased (d) both temperature and pressure are reduced

For the reaction: \(2 \mathrm{~A}+\mathrm{B} \rightleftharpoons \mathrm{C}+\mathrm{D}\) On doubling the concentration of \(C\), the value of equilibrium constant. \(K_{c}\), would (a) double (b) Halve (c) increase by 2 (d) not change

For the reaction \(2 A(g)+B(g) \rightleftharpoons 3 C(g)+D(g)\) Two moles each of \(A\) and \(B\) were taken into a 11 flask. The following must always be true when the system attained equilibrium (a) \([A]=[B]\) (b) \(|A|<[B \mid\) (c) \([B]=[C]\) (d) \(\\{A \mid+[B]<[C]+[D]\)

For the reaction \(\mathrm{CaCO}_{3}(\mathrm{~s})=\mathrm{CaO}(\mathrm{s})+\mathrm{CO}_{2}(\mathrm{~g})\), the addition of more of \(\mathrm{CaO}(\mathrm{s})\) causes (a) decrease in the concentration of \(\mathrm{CO}_{2}(\mathrm{~g})\) (b) increase in the concentration of \(\mathrm{CO}_{2}(\mathrm{~g})\) (c) change in the concentration of \(\mathrm{CO}_{2}(\mathrm{~g})\) (d) increase in the concentration of \(\mathrm{CaCO}_{3}(\mathrm{~s})\)

For the system, \(3 A+2 B=C\) the expression for equilibrium constant is (a) \([A]^{3}[B]^{2} /[C]\) (b) \([C] / A]^{3}[B]^{2}\) (c) \([A]^{2}[B]^{3} /[C]\) (d) \([C \mid /[A][B]\)

At constant pressure, upon the addition of helium at the equilibrium point in the reaction \(\mathrm{PCl}_{3}(\mathrm{~g})=\mathrm{PCl}_{3}(\mathrm{~g})+\mathrm{Cl}_{2}(\mathrm{~g})\), the degree of dissociation of (a) PCls will decrease (b) \(\mathrm{PCl}_{5}\) will increase (c) \(\mathrm{PCl}_{3}\) will increase (d) \(\mathrm{Cl}_{2}\) will increase

\(\mathrm{BiCl}_{3}\) (aq) \(+\mathrm{H}_{2} \mathrm{O}\) (1) \(\rightarrow \mathrm{BiOCl}(\mathrm{s})+2 \mathrm{HCl}\) (aq). If a little conc. \(\mathrm{HCl}\) is added (a) the solution becomes cloudier (b) the solution becomes clearer (c) nothing happens (d) data insufficient to conclude

In the manufacture of ammonia by haber's process $$ \mathrm{N}_{2}(\mathrm{~g})+3 \mathrm{H}_{3}(\mathrm{~g})=2 \mathrm{NH}_{3}(\mathrm{~g})+92.3 \mathrm{~kJ} $$ Which of the following conditions is unfavourable? (a) increasing the temperature (b) increasing the pressure (c) reducing the temperature (d) removing ammonia as it is formed

In the manufacture of ammonia by haber's process $$ \mathrm{N}_{2}(\mathrm{~g})+3 \mathrm{H}_{3}(\mathrm{~g})=2 \mathrm{NH}_{3}(\mathrm{~g})+92.3 \mathrm{~kJ} $$ Which of the following conditions is unfavourable? (a) increasing the temperature (b) increasing the pressure (c) reducing the temperature (d) removing ammonia as it is formed

\(\mathrm{CaCO}_{3}=\mathrm{CaO}+\mathrm{CO}_{2}\) reaction in a lime kiln goes to completion because (a) \(\mathrm{CaO}\) does not react with \(\mathrm{CO}_{2}\) to give \(\mathrm{CaCO}_{3}\) (b) Backward reaction is very slow (c) \(\mathrm{CO}_{2}\) formed escapes out (d) None of these

The standard state Gibb's free energy change for the i. cis-2-pentene = trans-2-pentene is \(-3.67 \mathrm{~kJ} \mathrm{~mol}\) at \(400 \mathrm{~K}\). If more trans-2-pentene is added to the reaction vessel (a) more cis-2-pentene is formed (b) equilibrium shifts in the forward direction (c) equilibrium remains unaltered (d) more trans-2-pentene is produced