Reaction Quotient

Q. The standard Gibbs energy channge at 300 K for the reaction, $2A\rightleftharpoons B+C$ is 2494. 2J. At a given time, the composition of the reaction mixture is $\left[A\right]=\frac{1}{2},\left[B\right]=2$ and $\left[C\right]=\frac{1}{2}.$ The reaction proceeds in the (R = 8.314JK / mol, e = 2.718)

1. forward direction because $Q>K_c$
2. reverse direction because $Q>K_c$
3. forward direction because $Q>K_c$
4. reverse direction because $Q<K_c$

Q. The free energy of formation of NO is $78kJmo{l}^{-1}$ at the temperature of $1000K$. What is the equilibrium constant for this reaction at $1000K$?
$\frac{1}{2}{N}_2\left(g\right)+\frac{1}{2}{O}_2\left(g\right)\rightleftharpoons NO\left(g\right)$

1. $8.4\times {10}^{-5}$
2. $7.1\times {10}^{-9}$
3. $4.2\times {10}^{-10}$
4. $1.7\times {10}^{-19}$

Q. The equilibrium constant $\left(K_c\right)$ for the reaction $N_2\left(g\right)+O_2\left(g\right)\to 2NO\left(g\right)$ at temperature T is $4\times {10}^{-4}$. The value of $K_c$ for the reaction
$NO\left(g\right)\to \frac{1}{2}{N}_2\left(g\right)+\frac{1}{2}{O}_2\left(g\right)$ at the same temperaure is

1. $0.02$
2. $2.5\times {10}^2$
3. $50.0$
4. $4\times {10}^{-4}$

Q.

At 298 K and 1 atm pressure, the partial pressures in an equilibrium mixture of $N_2{O}_4$ and $N{O}_2$ are 0.7 and 0.3 atmosphere respectively. What will be the partial pressure of $N{O}_2$ when the gases are in equilibrium at 298 K and at a total (equilibrium) pressure of 10 atmospheres?

1. 1.078 atm

2. 2.23 atm

3. 0.77 atm

4. 1.60 atm

Q. The equilibrium constant $K_P$ for the reaction
$N_2{O}_4\left(g\right)\rightleftharpoons 2N{O}_2$ (g) is $4.5$.
What would be the average molar mass (in g⁄mol) of an equilibrium mixture of $N_2{O}_4$ and $N{O}_2$ formed by the dissociation of pure $N_2{O}_4$ at a total pressure of 2 atm?

1. $57.5$
2. $85.5$
3. $80.5$
4. $69$

Q. The standard Gibbs energy change at 300 $K$ for the reaction $2A\rightleftharpoons B+C$ is 2494.2 $J$. At a given time, the composition of the reaction mixture is [A] = $\frac{1}{2}$, [B] = 2 and [C] =$\frac{1}{2}$ . The reaction proceeds in the: ($R$=8.314 $J{K}^{-1}mo{l}^{-1},e=2.718$)

1. forward direction because $Q>K_c$
2. forward direction because $Q<K_c$
3. reverse direction because $Q>K_c$
4. reverse direction because $Q<K_c$

Q. Given four reactions and their equilibrium constants.

$N_2{O}_2\rightleftharpoons 2NO,K_1;\frac{1}{2}{N}_2+\frac{1}{2}{O}_2\rightleftharpoons NO,K_2;$
$2NO\rightleftharpoons N_2+O_2,K_3;NO\rightleftharpoons \frac{1}{2}{N}_2+\frac{1}{2}{O}_2,K_4$
Correct relation between $K_1,K_2,K_{3}and{K}_4$ is:

1. $(K_4{)}^2=K_3$
2. $\sqrt{K_3}\times K_2=1$
   
3. None of the above
4. both a and b

Q. The $K_P$ value for the reaction $H_2\left(g\right)+I_2\left(g\right)\rightleftharpoons 2HI\left(g\right)$ at $460{}^{o}C$ is 49. If the initial pressure of $H_2$ and $I_2$ is $0.5atm$ respectively, determine the partial pressure of $H_2$ at equilibrium.

1. $0.22atm$
2. $0.11atm$
3. $0.02atm$
4. $0.01atm$

Q. For the following reaction:
$PC{l}_5\left(g\right)\rightleftharpoons PC{l}_3\left(g\right)+C{l}_2\left(g\right)$
$0.4mol$ of $PC{l}_5\left(g\right)$, $0.2mol$ of $PC{l}_3\left(g\right)$ and $0.6mol$ of $C{l}_2\left(g\right)$ are taken in a $1L$ flask.
If $K_c=0.2$, then the direction in which reaction proceeds is :

1. Towards reactant side
2. Towards products side
3. Reaction is at equilibrium
4. None of the above

Q. Which of the following statements about the reaction quotient, Q , are correct?

1. The reaction quotient, Q and the equilibrium constant always have the same value
2. Q may be greater than or less than or equal to the value of $K_c$
3. Value of Q does not depend on concentration of the products in a reaction
4. Q =1 at equilibrium