Effect on Kc

Q. The van't Hoff factor for $0.1\text{M},Ba(N{O}_3{)}_2$ solution is $2.74$. The degree of dissociation is:

1. $91.3\%$
2. $87\%$
3. $100\%$
4. $74\%$

Q. Given the reaction between $2$ gases represented by $A_2$ and $B_2$ to give the compound $AB\left(g\right)$.
$A_2\left(g\right)+B_2\left(g\right)\rightleftharpoons 2AB\left(g\right)$
At equilibrium, the concentration of:
$A_2=3.0\times {10}^{-3}\text{M}$
$B_2=4.2\times {10}^{-3}\text{M}$
$AB=2.8\times {10}^{-3}\text{M}$
If the reaction takes place in a sealed vessel at $527{}^{\circ }\text{C}$, then the value of $K_c$ will be:

1. $0.62$
2. $2.0$
3. $1.9$
4. $4.5$

Q. Equilibrium constant, $K_C$ for the reaction
$N_2\left(g\right)+3H_2\left(g\right)\rightleftharpoons 2N{H}_3\left(g\right)$ at $500K$ is $0.061$
At a particular time, the analysis shows that composition of the reaction mixture is $3.0mol{L}^{-1}{N}_2,2.0mol{L}^{-1}{H}_2$ and $0.5mol{L}^{-1}N{H}_3.$ Is the reaction at equilibirium and if not in which direction does the reaction tend to proceed to reach equilibrium?

1. at equilibrium
2. not at equilibrium, backwards shift
3. not at equilibrium, forward shift
4. can not be predicted

Q. $A\left(g\right)+3B\left(g\right)\rightleftharpoons 4C\left(g\right)$ initial concentration of A is equal to that of B. The equilibrium concentration of A and C are equal. $K_c$ of the reaction will be:

1. $0.08$
2. $8$
3. $80$
4. $0.8$

Q.

Why catalyst does not affect the equilibrium?

Q.

What happens to equilibrium when a catalyst is added?

Q. If the equilibrium constant for $N_2\left(g\right)+O_2\left(g\right)\rightleftharpoons 2NO\left(g\right)$ is $K$, the equilibrium constant for $\frac{1}{2}{N}_2\left(g\right)+\frac{1}{2}{O}_2\left(g\right)\rightleftharpoons NO\left(g\right)$ will be:

1. $K^{1/2}$
2. $\frac{1}{2}K$
3. $K$
4. $K^2$

Q.

What is the rate expression for the reverse reaction?

$2{\mathrm{H}}_2\left(\mathrm{g}\right)+2\mathrm{NO}\left(\mathrm{g}\right)\rightleftharpoons {\mathrm{N}}_2\left(\mathrm{g}\right)+2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$

The observed rate expression is $\mathrm{rate}={\mathrm{K}}_{\mathrm{f}}{\left[\mathrm{NO}\right]}^2\left[{\mathrm{H}}_2\right]$.

1. ${\mathrm{K}}_{\mathrm{b}}\left[{\mathrm{N}}_2\right]{\left[{\mathrm{H}}_2\mathrm{O}\right]}^2$

2. ${\mathrm{K}}_{\mathrm{b}}\left[{\mathrm{N}}_2\right]\left[{\mathrm{H}}_2\mathrm{O}\right]$

3. ${\mathrm{K}}_{\mathrm{b}}\frac{\left[{\mathrm{N}}_2\right]{\left[{\mathrm{H}}_2\mathrm{O}\right]}^2}{\left[{\mathrm{H}}_2\right]}$

4. ${\mathrm{K}}_{\mathrm{b}}\frac{\left[{\mathrm{N}}_2\right]{\left[{\mathrm{H}}_2\mathrm{O}\right]}^2}{\left[\mathrm{NO}\right]}$

Q. Diazonium salt decomposes as
$C_6{H}_5{N}_2^{+}\to C_6{H}_{5}Cl+N_2$
At $0^{o}C$, the evolution of $N_2$ becomes two times faster when the initial concentration of the salt is doubled. Therefore, it is:

1. A first order reaction
2. A second order reaction
3. Independent of the initial concentration of the salt
4. A zero order reaction

Q. For the reaction $3A\left(g\right)+B\left(g\right)\rightleftharpoons 2C\left(g\right)$ at a given temperature, $K_c=90$.What must be the volume of the flask, if a mixture of $2.0mol$ each of $A,B$ and $C$ exist in equilibrium?

1. $36L$
2. None of these
3. $6L$
4. $9L$

Q. For the reaction $H_2\left(g\right)+I_2\left(g\right)\rightleftharpoons 2HI\left(g\right)$,
If $0.5$ mole $H_2$ is reacted with $0.5$ mole $I_2$ in a ten-litre container at ${444}^{o}C$ and at same temperature value of equilibrium constant $K_c$ is $49$, the ratio for $\left[HI\right]$ and $\left[I_2\right]$ will be:

1. $7$
2. $\frac{1}{7}$
3. $\sqrt{\frac{1}{7}}$
4. $49$

Q. The degree of dissociation of $PC{l}_5$ at a certain temperature and $1\text{atm}$ pressure is $0.40$. Calculate the value of equilibrium constant $K_p$.
$PC{l}_5\left(g\right)\rightleftharpoons PC{l}_3\left(g\right)+C{l}_2\left(g\right)$

1. $0.19$
2. $0.26$
3. $0.15$
4. $0.29$

Q. 57. The rate equation for an autocatalytic reaction A + R = R + R is -d[A]/dt = k[A][R] Prove that when the rate of disappearance of reactant A is maximum then [A]=[R]

Q.

K1 and K2 are equilibrium constant for reaction (1) & (2)
${\mathrm{N}}_2\left(\mathrm{g}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\rightleftharpoons 2\mathrm{NO}\left(\mathrm{g}\right)$ …(1)

$NO\left(g\right)\rightleftharpoons \frac{1}{2}{N}_2\left(g\right)+\frac{1}{2}{O}_2\left(g\right)$ …(2)
Then,

1. $K_1=\frac{1}{K_2^2}$

2. $K_1=K_2^2$

3. $K_1=\frac{1}{K_2}$

4. $K_1={\left(K_2\right)}^o$

Q.

A catalyst has no effect on _________.

Q. $K_1\text{and}{K}_2$ are equilibrium constants for reactions (i) and (ii) respectively.
$N_{2\left(g\right)}+O_{2\left(g\right)}\rightleftharpoons 2N{O}_{\left(g\right)}$ ...(i)
$N{O}_{\left(g\right)}\rightleftharpoons \frac{1}{2}{N}_{2\left(g\right)}+\frac{1}{2}{O}_{2\left(g\right)}$ ...(ii)

1. $K_1={\left(\frac{1}{K_2}\right)}^2$
2. $K_1=K_2^2$
3. $K_1=\frac{1}{K_2}$
4. $K_1=(K_2{)}^1$

Q. A reaction system in equilibrium according to reaction $2S{O}_2\left(g\right)+O_2\left(g\right)\rightleftharpoons 2S{O}_3\left(g\right)$ in one litre vessel at a given temperature was found to be $0.12\text{mol}$ each $S{O}_2$ and $S{O}_3$ and $5$ mole of $O_2$.In another vessel of one litre contains $32\text{g}$ of $S{O}_2$ at tempreture.What mass in grams of $O_2$ must be added to this vessel to order that at equilibrium $20\%$ of $S{O}_2$ in oxidized to$S{O}_2$?

Q. For the reaction, $A_{\left(g\right)}+2B_{\left(g\right)}\rightleftharpoons 2C_{\left(g\right)},$ the rate constants for the forward and the reverse reactions are $1\times {10}^{-4}$ and $2.5\times {10}^{-2}$ respectively. The value of equilibrium constant, K for the reaction would be

1. 
   $1\times {10}^{-4}$
2. 
   $2.5\times {10}^{-2}$
3. 
   $4\times {10}^{-3}$
4. 
   $2.5\times {10}^2$

Q.

For the two gaseous reactions (i) and (ii), at ${25}^{\circ }C$

(i) $NO\left(g\right)+\frac{1}{2}{O}_2\left(g\right)\rightleftharpoons N{O}_2\left(g\right)$

(ii) $2N{O}_2\left(g\right)\rightleftharpoons 2NO\left(g\right)+O_2\left(g\right)$,

The equilibrium constants are $K_1$ and $K_2$ respectively are related as:

1. 

2. 

3. 

4. 

Q.

What is Le Chateliers principle?

Q.

Correct mathematical formulation Of First Law Of Thermodynamics used In thermochemistry is

1. $∆\mathrm{H}=∆\mathrm{U}-∆\mathrm{nRT}$

2. $∆\mathrm{U}=∆\mathrm{H}+∆\mathrm{nRT}$

3. $∆\mathrm{H}=∆\mathrm{U}+∆\mathrm{nRT}$

4. $∆\mathrm{H}=-∆\mathrm{U}+∆\mathrm{nRT}$

Q.

Will the limiting reagents always be the one which is in lesser quantity?

Q. The equilibrium,
$N{H}_{4}HS\left(s\right)\rightleftharpoons N{H}_3\left(g\right)+H_{2}S\left(g\right)$, is followed to set-up at $127{}^{\circ }\text{C}$ in a closed vessel. The total pressure at equilibrium was $20\text{atm}$. The $K_c$ for the reaction is:
(Given $R=0.08{\text{L atm K}}^{-1}{\text{mol}}^{-1}$)

1. $1.04{\text{M}}^2$
2. $0.097{\text{M}}^2$
3. $0.085{\text{M}}^2$
4. $3.045{\text{M}}^2$

Q. In a container equilibrium, $N_2{O}_4\left(g\right)\rightleftharpoons 2N{O}_2\left(g\right)$ is attained at ${25}^{\circ }C$. The total equilibrium pressure in container is $380\text{torr}$. If equilibrium constant of above equilibrium is $0.667\text{atm}$, then degree of dissociation of $N_2{O}_4$ at this temperature will be:

1. $\frac{1}{3}$
2. $\frac{1}{2}$
3. $\frac{2}{3}$
4. $\frac{1}{4}$

Q.

The following equilibria are given: $N_2$ +3$H_2$ $\leftrightharpoons$ $2N{H}_3$ $K_1$ ; $N_2$ + $O_2$ $\leftrightharpoons$ 2NO $K_2$ ;
$H_2$ + $\frac{1}{2}$ $O_2$ $\leftrightharpoons$ $H_{2}O{K}_3$ ;

The Equilibrium constant for the reaction $2N{H}_3$ + $\frac{5}{2}$ $O_2$ $\leftrightharpoons$ 2NO + 3$H_2$ O in terms of $K_1$, $K_2$ and $K_3$ is:

1. 

2. 

3. 

4. 

Q. Iron filling and water were placed in a 5 L vessel and sealed. The tank was heated to ${1000}^{\circ }$C. Upon analysis the tank was found to contain 1.1 g of hydrogen and 42.5 g of water vapour. If the reaction in the tank is represented by
$3Fe\left(s\right)+4H_{2}O\left(g\right)\rightleftharpoons F{e}_2{O}_4\left(s\right)+4H_2\left(g\right)$
the value of equilibrium constant $K_c$ is :

1. 30
2. 0.03
3. 3
4. 0.003

Q.

For the two gaseous reactions (i) and (ii), at ${25}^{0}C$

$\left(i\right)NO\left(g\right)+\frac{1}{2}{O}_2\left(g\right)⟵N{O}_2\left(g\right)$

$\left(ii\right)2N{O}_2\left(g\right)⟵2NO\left(g\right)+O_2\left(g\right)$,

The equilibrium constants are $K_1$ and $K_2$ respectively. these two constants are related as:

1. 

2. 

3. 

4. 

Q. Consider the reaction,
$2NO\left(g\right)+2H_2\left(g\right)=N_2\left(g\right)+2H_{2}O\left(g\right)$.
In the above reaction, by what factor would the reaction quotient change if the concentration of $NO$ was doubled?

1. $\frac{1}{4}$
2. 2
3. $\frac{1}{2}$
4. No change

Q. In hte following reaction
$2S{O}_2\left(g\right)+O_2\left(g\right)\rightleftharpoons 2S{O}_3\left(g\right)$
the equilibrium is not attained. The rate of forward reaction is greater than that of backward reaction. Thus, which of the following is the correct relation between $K_p$ and $Q_p$?

1. $K_p=Q_p$
2. $Q_p>K_p$
3. $Q_p<K_p$
4. $K_p=Q_p=1$

Q. $1$ mole each of $H_2\left(g\right)$ and $I_2\left(g\right)$ are introduced in a $1\text{L}$ eacuated vessel at $523K$ and equilibrium
$H_2\left(g\right)+I_2\left(g\right)\rightleftharpoons 2HI\left(g\right)$ is established. The concentration of $HI\left(g\right)$ at equilibrium:

1. Change on changing pressure
2. Changes on changing temperature
3. Change on changing volume of the vessel
4. Is same even if only $2\text{mol}$ of $HI\left(g\right)$ were introduced in the vessel in the beginning