Vant Hoff's Equation and Effect of Temperature on Equilibrium Constant

Q.

The molecular mass of $PC{l}_5$ is 208.32 but when heated to $230\circ C$, it is reduced to 124. The extent of dissociation of $PC{l}_5$ at this tempearature will be

1. 6.8%

2. 46%

3. 64%

4. 68%

Q.

\(N_2 ~+ ~O_2 ~\rightleftharpoons~ 2NO ~+~ (-Q cals)\)

In the above reaction which is the essential condition for the higher production of $NO$

1. High temperature

2. High pressure

3. Low temperature

4. Low pressure

Q. Consider a reaction:
$N_2\left(g\right)+3H_2\left(g\right)\rightleftharpoons 2N{H}_3\left(g\right)$
Given that ,
$K_{eq}=7\times {10}^5$
$\Delta S_{N{H}_3}^{\circ }=-23.66calmo{l}^{-1}{K}^{-1}$
Both the values are at 300K
Find the value of $\Delta H_{N{H}_3}^{\circ }$ at 300 K
Take $ln\left(7\right)=1.95$

1. $-15.16kcalmo{l}^{-1}$
2. $-35.46kcalmo{l}^{-1}$
3. $-85.2kcalmo{l}^{-1}$
4. $-65.4kcalmo{l}^{-1}$

Q. According to Van't Hoff equation, which of the following statement is correct regarding the plot of $\ln K_{eq}\text{v/s}\frac{1}{T}$ ?

1. For an endothermic reaction, the slope is $\frac{\Delta S^{\circ }}{RT}$
2. For an endothermic reaction, the slope is $\frac{-\Delta H^{\circ }}{R}$
3. For an exothermic reaction, the slope is $\frac{\Delta S^{\circ }}{R}$
4. For an exothermic reaction, the slope is $\frac{-\Delta H^{\circ }}{RT}$

Q. For the reaction H${}_2$ (g) + I${}_2$(g)$\rightleftharpoons$2HI(g), K${}^o$${}_c$= 66.9 at 350${}^{\circ }$C and K${}^o$${}_c$= 50.0 at 448 ${}^{\circ }$C. The reaction has

1. $\Delta$H = +ve.

2. $\Delta$H = -ve.

3. $\Delta$H = Zero

4. $\Delta$H whose sign cannot be predicted

Q. The reaction, $S{O}_2\left(g\right)+C{l}_2\left(g\right)\leftrightharpoons S{O}_{2}C{l}_2\left(l\right)$ is exothermic. A mixture of $S{O}_2,C{l}_2$ and $S{O}_{2}C{l}_2$ is at equilibrium in a closed container. Now, a certain amount of $S{O}_2$is added to the mixture, the volume remaining the same. Which of the following statement is true?

1. The pressure inside the container will not change
2. The temperature will not change
3. The temperature will increase
4. the temperature will decrease

Q. For the dissociation of $PC{l}_5\left(g\right)$
$PC{l}_5\left(g\right)\rightleftharpoons PC{l}_3\left(g\right)+C{l}_2\left(g\right)$
Slope of the linear curve is such that $\theta =ta{n}^{-1}(-2.1)$

Thus, $△H^o$ is

1. $28.72Jmo{l}^{-1}$
2. $-28.72Jmo{l}^{-1}$
3. $40.2Jmo{l}^{-1}$
4. $-12.47Jmo{l}^{-1}$

Q. In the following reversible reaction $2S{O}_2\left(g\right)+O_2\left(g\right)\rightleftharpoons 2S{O}_3\left(g\right),\Delta H=+Qcal$,
where Q is negative. Most suitable condition for a low production of $S{O}_3$ is:

1. High temperature and high pressure
2. High temperature and low pressure
3. Low temperature and high pressure
4. Low temperature and low pressure

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

Q.

\(N_2 ~+ ~O_2 ~\rightleftharpoons~ 2NO ~+~ (-Q cals)\)

In the above reaction which is the essential condition for the higher production of $NO$

1. High temperature

2. High pressure

3. Low temperature

4. Low pressure

Q. The variation of equilibrium constant ($K$) of a certain reaction with temperature ($T$) is $\ln K=3.0+\frac{2.0\times {10}^4}{T}$ given $R=8.3J{K}^{-1}mo{l}^{-1}$, the values of $\Delta H^o$ and $\Delta S^o$ are:

1. $\Delta H^o=-166kJ/mol$
2. $\Delta H^o=+166kJ/mol$
3. $\Delta S^o=+24.9kJ/mol$
4. $\Delta S^o=-24.9kJ/mol$

Q.

In the following reversible reaction $2S{O}_2+O_2\rightleftharpoons 2S{O}_3+QCal$

Most suitable condition for the higher production of $S{O}_3$ is

1. High temperature and high pressure

2. High temperature and low pressure

3. Low temperature and high pressure

4. Low temperature and low pressure

Q. Which of the following reaction will proceed in forward direction on decreasing the temperature?

1. $H_2\left(g\right)+I_2\left(g\right)\rightleftharpoons 2HI\left(g\right){\Delta }_{r}H=+3000\text{cal}$
2. $N_2\left(g\right)+O_2\left(g\right)\rightleftharpoons 2NO\left(g\right){\Delta }_{r}H=-43200\text{cal}$
3. $2N{H}_3\left(g\right)\rightleftharpoons N_2\left(g\right)+3H_2\left(g\right){\Delta }_{r}H=+22400\text{cal}$
4. $C{O}_2\left(g\right)\rightleftharpoons C\left(s\right)+O_2\left(g\right){\Delta }_{r}H=+94300\text{cal}$

Q.

The reaction A + B $\rightleftharpoons$​ C + D + heat has reached equilibrium. The reaction may

be made to proceed forward by

1. Adding more C

2. Adding more D

3. Decreasing the temperature

4. Removing A

Q.

For the chemical equilibrium, $CaC{O}_3\left(s\right)\rightleftharpoons CaO\left(s\right)+C{O}_2\left(g\right),\Delta H^{.}$, can be determined from which one of the following plots

1. 

2. 

3. 

4. 

Q.

The molecular mass of $PC{l}_5$ is 208.32 but when heated to $230\circ C$, it is reduced to 124. The extent of dissociation of $PC{l}_5$ at this tempearature will be

1. 6.8%

2. 46%

3. 64%

4. 68%