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

Q.

$\Delta G^{\circ }$ for the reaction $x+y\rightleftharpoons z$ is $-4.606kcal$. The value of equilibrium constant of the reaction at ${227}^{\circ }C$ is

1. 100

2. 10

3. 2

4. 0.01

Q.

For the reaction $2NO\left(g\right)\rightleftharpoons N_2\left(g\right)+O_2\left(g\right),\Delta H=-180kJmo{l}^{-1}$. Which of the following facts does not hold well?

1. The dissociation of NO is favored more at high temperature

2. The pressure changes at constant temperature do not affect the equilibrium constant

3. The volume changes at constant temperature do not affect the equilibrium constant

4. The dissociation of NO is favored less at high temperature

Q.

For a reaction $\Delta H=9.08kJmo{l}^{-1}$ and $\Delta S=35.7J{K}^{-1}mo{l}^{-1}$ Which of the following statements is correct for the reaction

1. Reversible and Isothermal

2. Reversible and Exothermic

3. Spontaneous and Endothermic

4. Spontaneous and Exothermic

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. Which of the following can not be predicted from an equilibrium constant for a reaction?

1. Nature of reactant and product.
2. whether a system is at equilibrium by measuring the concentrations of the reactants and products.
3. which direction a reaction will proceed by measuring the concentrations of reactants and products
4. The extent of a reaction

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.

If ${\mathrm{K}}_{\mathrm{c}}$ for the formation of $\mathrm{HI}$ from ${\mathrm{H}}_2$ and ${\mathrm{I}}_2$is 48 , then ${\mathrm{K}}_{\mathrm{c}}$ for decomposition of 1 mole of $\mathrm{HI}$ is________

Q. how does change in temperature change the value of equilibrium constant when the change is mediated by opting either endothermic or exothermic reaction??

Q.

What happens when pressure is increased in the following equilibrium rection

(i) N₂O₄(g)=2NO₂(g)

(ii) H₂(g)+I₂(g)=2HI(g)

Q.

The $\Delta H_f^{\circ }$ for $C{O}_2\left(g\right),CO\left(g\right)$ and $H_{2}O\left(g\right)$ are $-393.5,-110.5$ and $-241.8kJmol{e}^{-1}$ respectively. The standard enthalpy change in kJ for the reaction $C{O}_2\left(g\right)+H_2\left(g\right)\to CO\left(g\right)+H_{2}O\left(g\right)$ is

1. +524.1

2. +41.2

3. -262.5

4. -41.2

Q.

For a reaction $\Delta H=9.08kJmo{l}^{-1}$ and $\Delta S=35.7J{K}^{-1}mo{l}^{-1}$. Which of the following statements is correct for the reaction

1. Reversible and Isothermal

2. Reversible and Exothermic

3. Spontaneous and Endothermic

4. Spontaneous and Exothermic

Q.

Calculate $△G^{\ominus }$ for the following reaction:
$CO\left(g\right)+\frac{1}{2}{O}_2\left(g\right)\to C{O}_2\left(g\right)$; $△H^{\ominus }$ = -282.84 kJ
Given,
$S^{\ominus }C{o}_2=213.8J$ $K^{-1}mo{l}^{-1}$, $S^{\ominus }CO\left(g\right)$ = 197.9 J $K^{-1}mo{l}^{-1}$,
$S^{\ominus }C{o}_2=205.0J$ $K^{-1}mo{l}^{-1}$

1. -357 KJ

2. -383 KJ

3. -257 KJ

4. + 357 KJ

Q.

A reversible chemical reaction having two reactants in equilibrium. If the

concentrations of the reactants are doubled, then the equilibrium constant

will

1. Also be doubled

2. Be halved

3. Become one-fourth

4. Remain the same

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. The rate constant $\left(k\right)$ of a reaction is measured at different temperatures $\left(T\right)$, and the data are plotted in the given figure. The activation energy of the reaction in $kJmo{l}^{-1}$ is:
Here,
$R$ is gas constant :

1. $0.5R$
2. $R$
3. $1.5R$
4. $2R$

Q. Variation of equilibrium constant K for the reaction ; $2A\left(s\right)+B\left(g\right)\rightleftharpoons C\left(g\right)+2D\left(g\right)$ is plotted against absolute T in figure as- $lnKVs\left(1/T\right)$ :

1. the forward reaction is exothermic
2. the forward reaction is endothermic
3. the slope of line is proportional to $\Delta H$
4. adding 'A' favours forward reaction
5. removing C favours forward reaction

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. Consider the gas-phase equilibrium, $2H_{2}O\left(l\right)\rightleftharpoons 2H_2\left(g\right)+O_2\left(g\right)$ $\Delta H=241.7kJ$, which of the following changes will decrease the equilibrium amount of water?

1. Adding more oxygen
2. Increasing the temperature at constant pressure
3. Increasing the pressure at constant temperature
4. Adding catalyst

Q.

For a given reversible reaction if the concentrations of the reactants are quadrupled, the equilibrium constant will be

1. be one fourth of the previous value

2. be quadrupled

3. remain the same

4. be halved

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.

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.

For an equilibrium reaction A (g) + B (g) $\rightleftharpoons$ C (g) + D (g), $\Delta H$ = -ve. An increase in temperature would cause

1. An increase in the value of $K_{eq}$

2. A decrease in the value of $K_{eq}$

3. No change in the value of $K_{eq}$

4. A change in $K_{cq}$ which cannot be qualitatively predicted