Introduction to Le Chatelier's Principle

Q.

What are the three characteristics of equilibrium?

Q. For the reversible reaction :
$N_2\left(g\right)+3H_2\left(g\right)\rightleftharpoons 2N{H}_3\left(g\right)+heat$
The equilibrium shifts in forward direction-

1. By increasing the concentration of $N{H}_3\left(g\right)$
2. By decreasing the pressure
3. By decreasing the concentrations of $N_2\left(g\right)$ and $H_2\left(g\right)$
4. By increasing pressure and decreasing temperature

Q.

What are the applications of the equilibrium constant?

Q.

Question 02
On dissolving sugar in water at room temperature solution feels cool to touch. Under which of the following cases dissolution of sugar will be most rapid?
(a) Sugar crystals in cold water (b) Sugar crystals in hot water
(b) Powdered sugar in cold water (d) Powdered sugar in hot water

Q. In the reaction, $2S{O}_2\left(g\right)+O_2\left(g\right)\rightleftharpoons 2S{O}_3\left(g\right)+X\text{cal}$, most favourable conditions of temperature and pressure for greater yield of $S{O}_3$ are:

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

Q. Which of the following conditions is favourable for the production of ammonia by Haber`s process?

1. High concentration of reactants
2. Low temperature and high pressure
3. Continuous removal of ammonia
4. All of these

Q. 53. Show by using rate law how much rate of rhe reaction, 2NO + O2 -> 2NO2 will change if the volume of the reaction vessel is reduced to 1/3rd of its initial value.

Q.

Why do gases always tend to be less soluble in liquids as the temperature is raised?

Q. What will happen when the pressure is applied on a $ice\rightleftharpoons water$ system ?

1. More water will form
2. More ice will form
3. There will be no effect over equilibrium
4. 
   Water will decompose in $H_2$and $O_2$
   

Q. When sulphur in the form of $S_8$ is heated at $900K$, the initial pressure of one $atm$ of $S_{\left(8\right)}$ falls by 29% at equilibrium. This is because of conversion of some $S_8$ to $S_2.$ Find the value of equilibrium constant for this reaction.

1. $0.71$
2. $2.55$
3. $5.1$
4. $1.16$

Q. Given reaction is $2X\left(gas\right)+Y\left(gas\right)\rightleftharpoons 2Z\left(gas\right)+80kcal$ Which combination of pressure and temperature gives the highest yield of Z at equilibrium?

1. 
   $1000\text{atm}$ and $500{}^{o}C$
   
2. $500\text{atm}$ and $500{}^{o}C$
3. $1000\text{atm}$ and $100{}^{o}C$
4. $500\text{atm}$ and $100{}^{o}C$

Q. When hydrochloric acid is added to cobalt nitrate solution at room temperature, the following reaction takes place and the reaction mixture becomes blue. On cooling the mixture it becomes pink. On the basis of this information mark the correct answer.

$\underset{pink}{\underset{}{\left[Co\right(H_{2}O{)}_6{]}^{3^{+}}\left(aq\right)}}+4C{l}^{-}\left(aq\right)\leftrightharpoons \underset{blue}{\underset{}{\left[C_{o}C{l}_4{]}^{2^{-}}\right(aq)}}+6H_{2}O\left(l\right)$

1. 
2. 
3. 
4. 

Q. In which of the following system, doubling the volume of the container cause a shift to the right?

1. $2C{O}_{\left(g\right)}+O_{2\left(g\right)}\rightleftharpoons 2C{O}_{2\left(g\right)}$
2. $H_{2\left(g\right)}+C{l}_{2\left(g\right)}\rightleftharpoons 2HC{l}_{\left(g\right)}$
3. $N_{2\left(g\right)}+3H_{2\left(g\right)}\rightleftharpoons 2N{H}_{3\left(g\right)}$
4. $PC{l}_{5\left(g\right)}\rightleftharpoons PC{l}_{3\left(g\right)}+C{l}_{2\left(g\right)}$

Q. At $527{}^o\text{C}$, the reaction given below has $K_c=4$
$N{H}_3\left(g\right)\rightleftharpoons \frac{1}{2}{N}_2\left(g\right)+\frac{3}{2}{H}_2\left(g\right)$

What is the value of $K_p$ for the reaction given below?
$N_2\left(g\right)+3H_2\left(g\right)\rightleftharpoons 2N{H}_3\left(g\right)$

1. $16\times (800R{)}^2$
2. ${\left(\frac{800R}{4}\right)}^{-2}$
3. ${\left(\frac{1}{4\times 800R}\right)}^2$
4. None of these

Q.

CO + 2 H₂ -----> CH₃OH

Describe the effect of:

a) Addition of $H_2$
b) Addition of $C{H}_{3}OH$
c) Removal of CO
d) Removal of $C{H}_{3}OH$ on the equilibrium of the reaction:

Q.

Ice and water are placed in a closed container at a pressure of 1 atm and temperature 273.15 K. If pressure of the system is increased to 2 atm while keeping temperature constant, which of the following would be the correct observation ?

1. Volume of the system increases

2. The solid phase (ice) disappears completely

3. The liquid phase disppears completely

4. The amount of ice decreases

Q. Following two equilibrium is simultaneously established in a container
$PC{l}_5\left(g\right)\rightleftharpoons PC{l}_3\left(g\right)+C{l}_2\left(g\right)$
$CO\left(g\right)+C{l}_2\left(g\right)\rightleftharpoons COC{l}_2\left(g\right)$
If some $Ni\left(s\right)$ is introduced in the container forming $Ni\left(CO{)}_4\right(g)$ then at new equilibrium

1. $PC{l}_3$ concentration will increase
2. $PC{l}_3$ concentration will decrease
3. $C{l}_2$ concentration will remain same
4. $CO$ concentration will remain same

Q. A salt AB crystallises in the CsCl structure. The anions at the corners and the cation in the centre, hence radius ratio $\left(\frac{r_t}{r}\right)$ is

1. 0.225
2. 0.441
3. 0.732
4. 0.625

Q. Le Chatelier principle is_________.

1. reaction of a system to maintain equilibrium
2. cybernetics
3. carrying capacity
4. feedback

Q.

Some quantity of water is contained in a container as shown in figure. As neon is added to this system at constant pressure, the amount of water vapour in the vessel.

1. increases

2. decreases

3. remains same

4. changes unpredictably

Q. Consider the reaction
$HCN\left(aq\right)\rightleftharpoons H^{+}\left(aq\right)+C{N}^{-}\left(aq\right)$ , At equilibrium, the addition of $C{N}^{-}\left(aq\right)$ would

1. Reduce $HCN\left(aq\right)$ concentration
2. Decrease the $H^{+}\left(aq\right)$ ion concentration
3. Increase the equilibrium constant
4. Decrease the equilibrium constant

Q. Following data is given for the reaction: $CaC{O}_3\left(s\right)\to CaO\left(s\right)+C{O}_2\left(g\right)$
${\Delta }_f{H}^o\left[CaO\right(s\left)\right]=-635.1{\text{kJ mol}}^{-1}$
${\Delta }_f{H}^o\left[C{O}_2\right(g\left)\right]=-393.5{\text{kJ mol}}^{-1}$
${\Delta }_f{H}^o\left[CaC{O}_3\right(s\left)\right]=-1206.9{\text{kJ mol}}^{-1}$
Predict the effect of temperature on the equilibrium constant of the above reaction.

1. On increasing temperature, equilibrium will shift in forward direction
2. On increasing temperature, equilibrium will shift in backward direction
3. Equilibrium will remain unchanged on decreasing the temperature
4. Equilibrium will remain unchanged on increasing the temperature

Q. A graph of vapour pressure and temperature for the three different liquids $X,Y$ and $Z$ is shown:
The following interference are made:
$\left(A\right)X$ has higher intermolecular interaction compared to $Y$.
$\left(B\right)X$ has lower intermolecular interaction compared to $Y$.
$\left(C\right)Z$ has lower intermolecular interaction compared to $Y$.
The correct interfernce(s) is/are:

1. $\text{(A) and (C)}$
2. $\text{(A)}$
3. $\text{(C)}$
4. $\text{(B)}$

Q. Le-chatelier principle is applicable

1. Both for physical and chemical equilibrium
2. Only for chemical equilibrium
3. Only for physical equilibrium
4. Neither for B nor for C

Q. In which of the following equilibrium reactions the equilibrium would shift to the right, if total pressure is increased?

1. $N_2\left(g\right)$ + $3H_2\left(g\right)$ $\rightleftharpoons$ $2N{H}_3\left(g\right)$
2. $H_2\left(g\right)$ + $I_2\left(g\right)$ $\rightleftharpoons$ $2HI\left(g\right)$
3. $H_2\left(g\right)$ + $C{l}_2\left(g\right)$ $\rightleftharpoons$ $2HCl\left(l\right)$
4. $N_2{O}_4\left(s\right)$ $\rightleftharpoons$ $2NO\left(g\right)$

Q.

Le Chateliers principle is applicable to__________

Q.

Does equilibrium constant change with temperature?

Q. The effect of increasing the pressure on the equilibrium $2A\left(g\right)+3B\left(g\right)\rightleftharpoons 3A\left(g\right)+2B\left(g\right)$ is

1. Forward reaction is favoured
2. Backward reaction is favoured
3. No effect
4. None of the above

Q. In the gaseous equilibrium
$H_2{X}_2\left(g\right)+heat\rightleftharpoons 2HX\left(g\right)$, the formation of $HX$ will be favoured by

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

Q. For the reaction
$2Cl{F}_3\left(g\right)\rightleftharpoons C{l}_2\left(g\right)+3F_2\left(g\right)$
$log{K}_{eq}v/s\frac{1}{T}$ (where temperature is in K) curve is obtained as following
Which of the following change will increase the concentration of $C{l}_2$ in an equilibrium mixture of $C{l}_2,F_{2}andCl{F}_3:$

1. Addition of inert gas at constant pressure
   
2. Increase in temperature at constant volume
   
3. Addition of catalyst at equilibrium
   
4. Removal of $F_2\left(g\right)$ at equilibrium