Characteristics of Equilibrium Constant

Q.

What is rate constant?

Q. Two substances $A(t_{\frac{1}{2}}=5\text{min})$ and $B(t_{\frac{1}{2}}=15\text{min})$ are taken in such a way that initially $\left[A\right]=4\left[B\right]$. The time after which both the concentration will be equal is: (Assume that reaction is first order)

1. $5min$
2. $15min$
3. Concentration can never be equal
4. $20min$

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.

What is equilibrium and its types?

Q. For the reaction $C\left(s\right)+C{O}_2\left(g\right)\rightleftharpoons 2CO\left(g\right),$ the partial pressure of $C{O}_2$ and CO is 2.0 and 4.0 atm, resprectively at equilibrium, The $k_p$ of the reaction is:

1. $8atm$
2. $16atm$
3. $12atm$
4. None of these

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. Calculate the degree of dissociation of $HI$ as $2HI\rightleftharpoons H_2+I_2$ at $450{}^{o}C$ , if the equilibrium constant for the dissociation reaction is 0.263.

1. $0.688$
2. $0.326$
3. $0.454$
4. $0.253$

Q.

What is equilibrium process?

Q. A mixture of $N{H}_3\left(g\right)$ and $N_2{H}_4\left(g\right)$ is placed in a sealed container at $27{}^{\circ }\text{C}$, $0.5\text{atm}$. After complete decomposition of $N{H}_3$ and $N_2{H}_4$ at $927{}^{\circ }\text{C}$ the total pressure is reached to $4.5\text{atm}$.
The decomposition reactions are as follow:
$2N{H}_3\left(g\right)\to N_2\left(g\right)+3H_2\left(g\right)N_2{H}_4\left(g\right)\to N_2\left(g\right)+2H_2\left(g\right)$
The percentage of $N{H}_3$ (by mole) is:

1. $75\%$
2. $25\%$
3. $40\%$
4. $60\%$

Q.

For a neutral solution which of the following statement(s) is/are correct ?

1. The molar concentration of $H_3{O}^{+}={10}^{-7}$ at $298K$..
2. The molar concentration of $O{H}^{-}={10}^{-7}$ at $298K$..
3. Both $H_3{O}^{+}$ and $O{H}^{-}$ ions are not present.
4. Both $H_3{O}^{+}$ and $O{H}^{-}$ ions are present in small but equal concentration.

Q.

For the reaction $H_2$ (g) + $I_2$ (g) $\leftrightharpoons$ 2HI(g)the equilibrium constant $K_p$ changes with

1. Total pressure

2. catalyst

3. the amounts of $H_2$ and $I_2$ present

4. temperature

Q.

The equilibrium constant in a reversible reaction at a given temperature

1. Depends on the initial concentration of the reactants

2. Depends on the concentration of the products at equilibrium

3. Does not depend on the initial concentrations

4. It is not characteristic of the reaction

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. 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. The value of equilibrium constant for self ionisation of water at ${25}^{\circ }C$ is (density of water 1 $g/ml$) :

1. $55.5\times {10}^{-18}$
2. $5.55\times {10}^{-18}$
3. $3.25\times {10}^{-18}$
4. $1\times {10}^{-18}$

Q. The equilibrium constant for the following reaction is 49 at ${450}^{o}C.$ If $0.22mol$ of $I_2$, $0.22mol$ of $H_2$ and $0.66mol$ of $HI$ were put in a evacuated 1 litre container.
$H_2+I_2\rightleftharpoons 2HI$
Then, the correct statement will be:

1. Reaction will proceed in forward direction until equilibrium is established.
2. Reaction will proceed in backward direction until equilibrium is established.
3. Reaction is already at equilibrium.
4. None of the above

Q. If $a$ is the degree of dissociation of $PC{l}_5$ at equilibrium for the reaction, $PC{l}_5\rightleftharpoons PC{l}_3+C{l}_2$
The total number of moles of the reaction Consider intial moles of $P$ to be 1:

1. $1-a$
2. $1+a$
3. 3
4. $1$

Q. In which of the following cases, the reaction with a given $K_c$ goes farthest towards completion?

1. $K_c=1$
2. $K_c={10}^{-1}$
3. $K_c={10}^{+5}$
4. $K_c=10$

Q. For the reaction $N_2+3H_2\rightleftharpoons 2N{H}_3,$ Initially $N_2:H_2$ were taken in the ratio of 1 : 3. Up to the point of equilibrium 50% each reactant has been reacted. If total pressure at equilibrium is P. The partial pressure of ammonia would be -

1. P/3
2. P/6
3. P/4
4. P/8

Q. $50\text{kg}$ of $N_2\text{(g)}$ and $10\text{kg}$ of $H_2$ are mixed to produce $N{H}_3\text{(g)}$. Calculate the amount of $N{H}_3\text{(g)}$ formed.
(assume the reaction goes to completion)
$N_2\left(g\right)+3H_2\left(g\right)\to 2N{H}_3\left(g\right)$

1. $56.67\text{kg}$
2. $51.87\text{kg}$
3. $50.71\text{kg}$
4. $47.67\text{kg}$

Q. For the reaction $H_2+I_2\rightleftharpoons 2HI$
The value of equilibrium constant is 9.0.
The degree of dissociation of HI will be?

1. 2
2. 2/5
3. 5/2
4. 1/2

Q.

$NaOH$ is a strong base because

1. It gives $O{H}^{-}$ ion.

2. It can be oxidised

3. It provides $H_3{O}^{+}$ ions.

4. It can be easily ionised

Q. In which of the following reactions the equilibrium constant will have no units?

1. $NO\left(g\right)\rightleftharpoons \frac{1}{2}{N}_2\left(g\right)+\frac{1}{2}{O}_2\left(g\right)$
2. $H_2\left(g\right)+l_2\left(g\right)\rightleftharpoons 2HI\left(g\right)$
3. $CO\left(g\right)+H_{2}O\left(g\right)\rightleftharpoons C{O}_2\left(g\right)+H_2\left(g\right)$
4. In all the above reactions

Q. What is the percentage relative humidity on a day, when partial pressure of water vapour is $0.012\times {10}^{5}Pa$ and temperature is ${12}^{\circ }C$.
The vapor pressure of water at this temperature is $0.016\times {10}^{5}Pa$

Q. For the combustion of benzene, which of the following relations is correct?

1. $\Delta H=\Delta U-3RT$
2. $\Delta H=\Delta U-1.5RT$
3. $\Delta H=\Delta U+3RT$
4. $\Delta H=\Delta U+1.5RT$

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. Pure ammonia is placed in a vessel at a temperature where its dissociation is appreciable. At equilibrium,

1. $K_p$ does not change significantly with pressure
2. $\alpha$ does not change with pressure
3. concentration of $N{H}_3$ does not change with pressure
4. concentration of $H_2$ is less than that of $N_2$

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. For the following reaction, the equilibrium constant $K_c$
at 298 K is $1.6\times {10}^{17}$
$F{e}^{2+}\left(aq\right)+S^{2-}\left(aq\right)\rightleftharpoons FeS\left(s\right)$
When equal volumes of $0.06MF{e}^{2+}\left(aq\right)and0.2M{S}^{2–}\left(aq\right)$
solutions are mixed, the equilibrium
concentration of $F{e}^{2+}\left(aq\right)$ is found to be $Y\times {10}^{–17}M.$ The value of Y is

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