Characteristics of Equilibrium Constant

Q. A nitrogen-hydrogen mixture initially in the molar ratio of 1:3 reached equilibrium to from ammonia when 25% of the N2 and H2 had reacted .If the pressure of the system was 21 atm , the partial pressure of ammonia at the equilibrium was

Q. Statement 1: The value of the equilibrium constant, K, depends on the temperature at which the reaction is happening.
Statement 2: A Catalyst is a substance which can change the speed of the chemical reaction without itself getting consumed

1. TT
2. TF
3. FT
4. FF

Q. For the hypothetical reactions, the equilibrium constant $\left(K\right)$ values are given:
$A\rightleftharpoons B;K_1=2B\rightleftharpoons C;K_2=4C\rightleftharpoons D;K_3=3$
The equilibrium constant for the reaction $A\rightleftharpoons D$ will be:

1. 48
2. 6
3. 24
4. 12

Q. In the chemical reaction $A+B\to AB;B$ is acting as a limiting reagent then choose the correct option.

AIIMS-MBBS-2019-26 May-Morning Q.80

1. $\text{A = 50 atm, B = 100 atm}$
2. $\text{A = 100 atm, B = 200 atm}$
3. $\text{A = 50 atm, B = 200 atm}$
4. $\text{A = 50 atm, B = 30 atm}$

Q.

The equilibrium constant for the reaction,

CaCO₃(s) ⇌ CaO(s) + CO₂ (g), is

1. 

2. 

3. 

4. 

Q. A reversible chemical reaction having two reactants in equilibrium. If the concentration 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. 22. Why there is opposite effect of pressure changes when del n is negative and positive according to Le chatlier principle?

Q. In an alkaline solution, the following equilibria exist.
$S^{2-}+S\to S_2^{2-}$equilibrium constant $K_1$
$S_2^{2-}+S\to S_3^{2-}$ equilibrium constant $K_2$
$K_1$ and $K_2$ have the values 12 and 11, respectively.
$S_3^{2-}\to S^{2-}+2S$. What is equilibrium constant for the reaction?

1. $132$
2. $7.58\times {10}^{-3}$
3. $1.09$
4. $0.198$

Q. For the following gaseous equilibria $X,YandZ$ at $300K$
$X:2S{O}_2+O_2\rightleftharpoons 2S{O}_3$
$Y:PC{l}_5\rightleftharpoons PC{l}_3+C{l}_2$
$Z:2HI\rightleftharpoons H_2+I_2$

The ratio of $K_p$ and $K_c$ in the increasing order will be:

1. X = Y = Z
2. X < Y < Z
3. X < Z < Y
4. Z < Y < X

Q. At ${87}^{o}C,$ the following equilibrium is established:
$H_2\left(g\right)+S\left(s\right)\rightleftharpoons H_{2}S\left(g\right),K_c=8\times {10}^{-2}$
If 0.3 mole of hydrogen and 2 mole of sulphur are heated to ${87}^{o}C$ in a 2 L vessel, what will be the partial pressure of $H_{2}S$ at equilibrium.

1. 0.32 atm
2. 1.43 atm
3. 0.62 atm
4. 4.0 atm

Q. When $NO$ and $N{O}_2$ are mixed, the following equilibria are readily obtained :
$2N{O}_2\rightleftharpoons N_2{O}_4{K}_p=6.8at{m}^{-1}$
and
$NO+N{O}_2\rightleftharpoons N_2{O}_3$
In an experiment when $NO$ and $N{O}_2$ are mixed in the ratio of $1:2$, the final total pressure was $5.05atm$ and the partial pressure of $N_2{O}_4$ was $1.7atm$. Calculate the equilibrium partial pressure of $NO$ in atmosphere :

1. $1.05atm$
2. $4atm$
3. $6atm$
4. $8atm$

Q. The equilibrium constant $K_c$ or $K_p$ for endothermic reaction increases with

1. Increase in temperature
2. Decreases in temperature
3. No effect of temperature
4. Increases in pressure

Q. Under a given set of experimental conditions , with increase in the concentration of the reactants , the rate of a chemical reaction.

1. Decreases
2. Increases
3. Remains unaltered
4. First decreases and then increases

Q. $N_2+3H_2\rightleftharpoons 2N{H}_3$, starting with one mole of nitrogen and 3 moles of hydrogen, at equilibrium 50% of each had reacted. If the equilibrium pressure is $P$, the partial pressure of hydrogen at equilibrium would be:

1. $\frac{P}{2}$
2. $\frac{P}{3}$
3. $\frac{P}{4}$
4. $\frac{P}{6}$

Q. Given:
$N_2\left(g\right)+3H_2\left(g\right)\rightleftharpoons 2N{H}_3\left(g\right);K_1$
$N_2\left(g\right)+O_2\left(g\right)\rightleftharpoons 2NO\left(g\right);K_2$
$H_2\left(g\right)+\frac{1}{2}{O}_2\left(g\right)\rightleftharpoons H_{2}O\left(g\right);K_3$
where $K_1,K_2,K_3$ are equilibrium constants.
The equilibrium constant for the reaction,
$2N{H}_3\left(g\right)+\frac{5}{2}{O}_2\left(g\right)\rightleftharpoons 2NO\left(g\right)+3H_{2}O\left(g\right)$ will be:

1. $K_1{K}_2{K}_3$
2. $\frac{K_1{K}_2}{K_3}$
3. $\frac{K_1{K}_3^2}{K_2}$
4. $\frac{K_2{K}_3^3}{K_1}$

Q. Consider the general hypothetical reaction:
$A\left(s\right)\leftrightharpoons 2B\left(g\right)+3C\left(g\right)$
If the concentration of C at equilibrium is doubled, then after the equilibrium is re-established, the concentration of B will be :

1. Twice of its original value
2. Half of its original value
3. $2\sqrt{2}$ times of original value
4. $\frac{1}{2\surd 2}$ times the original value

Q. Which one of the following statements is not correct?

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Q.

What indicator should be used (in terms of its $p{K}_{in}$)for the titration of 0.10 M $K{H}_{2}B{O}_3$ with 0.10 M $HCl$ ?

1. pK_in = 2.2

2. pK_in = 5.22

3. pK_in = 9.56

4. pK_in = 6.6

Q. For an equilibrium reaction, the rate constants for the forward and backward reactions are $2.38\times {10}^{-4}{s}^{-1}$ and $8.15\times {10}^{-5}{s}^{-1}$ respectively. The equilibrium constant for the reaction is:

1. 0.342
2. 2.92
3. 0.292
4. 3.42

Q. $C\left(s\right)+O_2\left(g\right)\underset{}{\overset{}{\to }}C{O}_2\left(g\right)\Delta H^{\circ }=-393.5{\text{kJ mol}}^{-1}$
$C\left(s\right)+\frac{1}{2}{O}_2\left(g\right)\underset{}{\overset{}{\to }}CO\left(g\right)\Delta H^{\circ }=-110.5{\text{kJ mol}}^{-1}$
$H_2\left(g\right)+\frac{1}{2}{O}_2\left(g\right)\underset{}{\overset{}{\to }}{H}_{2}O\left(g\right)\Delta H^{\circ }=-241.8{\text{kJ mol}}^{-1}$
The standard enthalpy change $\left({\text{in kJ mol}}^{-1}\right)$ for the reaction.
$C{O}_2\left(g\right)+H_2\left(g\right)⟶CO\left(g\right)+H_{2}O\left(g\right)$ is

1. $-262.2$
2. $+41.2$
3. $-41.2$
4. $+262.2$

Q. A vessel; at 1000 K contains $C{O}_2$ with a pressure of 0.5 atm. Some of the $C{O}_2$ is converted into CO on the addition of graphite. If the total pressure at equilibrium is 0.8 atm, the value of K is:

1. 1.8 atm
2. 3 atm
3. 0.3 atm
4. 0.18 atm

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

1. 
2. 
3. 
4. 

Q. Two solid compounds $X$ and $Y$ dissociates at a certain temperature as follows
$X\left(S\right)\rightleftharpoons A\left(g\right)+2B\left(g\right);K_{P1}=9\times {10}^{-3}at{m}^3$
$Y\left(s\right)\rightleftharpoons 2B\left(g\right)+C\left(g\right);K_{P2}=4.5\times {10}^{-3}at{m}^3$
The total pressure (in atm) of gases over a mixture of $X$ and $Y$ is :

Q. What is $K_c$ for the following equilibrium when the equilibrium concentration of each substance is: $\left[{SO}_2\right]=0.60M,\left|O_2\right|=0.82M$ and $\left[{SO}_3\right]=1.90M$ ?
$2{SO}_2\left(g\right)+O_2\left(g\right)\rightleftharpoons 2{SO}_3\left(g\right)$

Q. The degree of dissociation of $S{O}_3$ is $\alpha$ at equilibrium pressure P. $K_P$ for $S{O}_3\left(g\right)\rightleftharpoons S{O}_2\left(g\right)+\frac{1}{2}{O}_2\left(g\right)$

1. $\frac{P^2{\alpha }^2}{2(1-\alpha {)}^3}$
2. $\frac{P^{\frac{1}{2}}{\alpha }^{3/2}}{(1-\alpha )(2+\alpha {)}^{1/2}}$
3. $\frac{P^2{\alpha }^2}{2(1-\alpha {)}^2}$
4. None of these

Q. Match the following.
$\begin{array}{cc}\text{Reaction}& \text{Degree of dissociation in terms of}\\ \text{(Homogeneous gaseous phase)}& \text{equilibrium constant}\\ \text{(a)}A\left(g\right)+B\left(g\right)\rightleftharpoons 2C\left(g\right)& \text{(p)}\left(\sqrt{K}\right)/(1+\sqrt{K})\\ \text{(b)}2A\left(g\right)\rightleftharpoons B\left(g\right)+C\left(g\right)& \text{(q)}\left(\sqrt{K}\right)/(2+\sqrt{K})\\ \text{(c)}A\left(g\right)+B\left(g\right)\rightleftharpoons C\left(g\right)+D\left(g\right)& \text{(r)}2K/(1+2K)\\ \text{(d)}AB\left(g\right)\rightleftharpoons \frac{A}{2}\left(g\right)+\frac{B}{2}\left(g\right)& \text{(s)}\frac{2\sqrt{K}}{1+2\sqrt{K}}\\ & \text{(t) K}\end{array}$

1. $\text{a}–\text{q},\text{b}–\text{s},\text{c}-\text{p},\text{d}-\text{r}$
2. $\text{a}–\text{q},\text{b}–\text{p},\text{c}-\text{s},\text{d}-\text{r}$
3. $\text{a}–\text{r},\text{b}–\text{s},\text{c}-\text{p},\text{d}-\text{q}$
4. $\text{a}–\text{s},\text{b}–\text{p},\text{c}-\text{r},\text{d}-\text{q}$

Q.

[[Q]]

Calculate a) G°and b) the equilibrium constant for the formation of NO₂ from NO and O₂ at 298 K

where _fG° (NO₂) = 52.0 kJ/mol

_fG° (NO) = 87.0 kJ/mol

_fG° (O₂) = 0 kJ/mol

Q. For the equilibrium at ${27}^{o}C.$
$LiCl.3N{H}_3\left(s\right)\rightleftharpoons LiCl.N{H}_3\left(s\right)+2N{H}_3\left(g\right);K_P=9at{m}^2$
A 24.63 litre flask contain 1 mol $LiCl.N{H}_3.$ How many moles of $N{H}_3$ should be added to flask at this temperature to drive the backward reaction for completion.

1. 5 moles
2. 8 moles
3. 3 moles
4. 2 moles

Q. The equilibrium constants $K_{p1}$ and $K_{p2}$ for the reactions $X\rightleftharpoons 2Y$ and $Z\rightleftharpoons P+Q$, respectively are in the ratio of $1:9$. If degree of dissociation of $X$ and $Z$ be equal then the ratio if total pressures at these equlibria is

1. $1:9$
2. $1:36$
3. $1:1$
4. $1:3$

Q. Calculate the partial pressure of carbon monoxide from the following data:
$CaC{O}_3\left(s\right)\stackrel{\Delta }{⟶}CaO\left(s\right)+C{O}_2\left(g\right);K_p=8\times {10}^{-2}C{O}_2\left(g\right)+C\left(s\right)\to 2CO\left(g\right)K_p=2$

1. $0.2$
2. $0.4$
3. $1.6$
4. $4$