Law of Mass Action

Q. The volume of $C{O}_2$ obtained at STP by the decompostion of 10 g of calcium carbonate is:
(molar mass of calcium carbonate = 100 $gmo{l}^{-1}$

1. 2.24 L
2. 44.8 L
3. 67.2 L
4. 22.4 L

Q. Select the correct diagram for an endothermic reaction that proceeds through two steps, where the second step is rate determining:

1. 
2. 
3. 
4. 

Q.

Which of the following statements is correct according to the Law of mass action?

1. Under a given set of conditions, the rate of chemical reaction is directly proportional to the product of the concentration of the reacting substances

2. For a given temperature, the rate of a reaction is directly proportional to the product of molar concentrations of reacting species, each raised to a power equal to the corresponding stoichiometric coefficient appearing in the balanced chemical equation.

3. The Law of mass is only applicable for solids

4. Both a and b

Q. Which of the following is not a characteristics of equilibrium?

1. Rate of forward reaction is equal to the rate of backward reaction at equilibrium
2. Pressure, concentration, density remains constant at equilibrium
3. Equilibrium can be obtained by either side of a reaction
4. Equilibrium occurs only in open vessels at constant temperatures

Q. For which of the following reactions, $K_P=K_C$ ?

1. $PC{l}_3\left(g\right)+C{l}_2\left(g\right)\leftrightharpoons PC{l}_5\left(g\right)$
2. $H_2\left(g\right)+C{l}_2\left(g\right)\leftrightharpoons 2HCl\left(g\right)$
3. $N_2\left(g\right)+3H_2\left(g\right)\leftrightharpoons 2N{H}_3\left(g\right)$
4. $CaC{O}_3\left(s\right)+\leftrightharpoons CaO\left(s\right)+C{O}_2\left(g\right)$

Q. Theory of active mass indicates that the rate of chemical reaction is directly proportional to the

1. Equilibrium constant
2. Properties of reactants
3. Volume of apparatus
4. Concentration of reactants

Q.

Which of the following can change the value of the equilibrium constant for a reaction

1. changing reactants’ concentrations

2. adding a catalyst

3. changing the solvent

4. removing products as they form

Q. The following concentration were obtained for the formation of $N{H}_3$ form $N_2$ and $H_2$ at equilibrium for the reaction $N_2\left(g\right)+3H_2\left(g\right)\rightleftharpoons 2N{H}_3\left(g\right)$

$\left[N_2\right]=1.5\times {10}^{-2}M$
$\left[H_2\right]=3.0\times {10}^{-2}M$
$\left[N{H}_3\right]=1.2\times {10}^{-2}M$

Calculate equilibrium constant.

1. $310.0$
2. $536.0$
3. $556.0$
4. $356.0$

Q. Ammonia under a pressure of $15$ atm at ${27}^{\circ }C$ is heated to
${347}^{\circ }C$ in a closed vessel in the presence of a catalyst. Under the conditions, $N{H}_3$ is partially decomposed according to the equation,
$2N{H}_3\leftrightharpoons N_2+3H_2$ .The vessel is such that the volume remains effectively constant whereas pressure increases to
$50atm$. Calculate the percentage of $N{H}_3$ actually decomposed.

1. $65\%$
2. $61.3\%$
3. $62.5\%$
4. $64\%$

Q. For the reaction$4N{H}_3\left(g\right)+5O_2\left(g\right)\rightleftharpoons 4NO\left(g\right)+6H_{2}O\left(g\right),$, the expression of $K_c$ will be:

1. $K_c=\frac{\left[NO{]}^4\right[H_{2}O{]}^6}{\left[N{H}_3{]}^4\right[O_2{]}^5}$
2. $K_c=\frac{\left[N{H}_3{]}^4\right[O_2{]}^5}{\left[NO{]}^4\right[H_{2}O{]}^6}$
3. $K_c=\frac{\left[N{H}_3\right]\left[O_2\right]}{\left[NO\right]\left[H_{2}O\right]}$
4. $K_c=\frac{\left[NO\right]\left[H_{2}O\right]}{\left[N{H}_3\right]\left[O_2\right]}$

Q. $NO$ and $B{r}_2$ at initial partial pressures of 98.4 and 41.3 $\text{torr}$, respectively, were allowed to react at $300\text{K}$. At equilibrium the total pressure was $110.5\text{torr}$. Calculate the value of the equilibrium constant ($Kp$) at $300\text{K}$, for the reaction $2NO\left(g\right)+B{r}_2\left(g\right)\rightleftharpoons 2NOBr\left(g\right).$

1. $134at{m}^{-1}$
2. $164at{m}^{-1}$
3. $234at{m}^{-1}$
4. $264at{m}^{-1}$

Q. In the thermal decomposition of patassium chlorate given as $2KCl{O}_3(aq.)\to 2KCl(aq.)+3O_2\left(g\right)$
Here, law of mass action:

1. Cannot be applied
2. Can be applied
3. Can be applied at low temperature
4. Can be applied at high temp. and pressure

Q.

For the reaction $A+2B\rightleftharpoons C+D,$ the equilibrium constant is $1.0\times {10}^8$. Calculate the equilibrium concentration of A if 1.0 mole of A and 3.0 mole of B are placed in 1L flask and allowed to attain the equilibrium ?

1. $1.0\times {10}^{-2}mol{L}^{-1}$

2. $2.1\times {10}^{-4}mol{L}^{-1}$

3. $5\times {10}^{-5}mol{L}^{-1}$

4. $1.0\times {10}^{-8}mol{L}^{-1}$

Q.

NX is produced by the following step of reactions M + $X_2$$⟶$$M{X}_2$$⟶$$M{X}_2$+$X_2$$⟶$$M_3{X}_8$

$M_3{X}_8$+$N_{2}C{O}_3$$⟶$NX +$C{O}_2$+$M_3{O}_4$ How much M (metal) is consumed to produce 206 gm of NX. (Take at wt. of M = 56, N = 23, X = 80)

1. 42 g

2. 56 g

3. $\frac{14}{3}g$

4. $\frac{7}{4}g$

Q.

The active mass of a solid is taken to be unity - true or false?

1. True

2. False

Q. In the thermal decomposition of patassium chlorate given as $2KCl{O}_3(aq.)\to 2KCl(aq.)+3O_2\left(g\right)$
Here, law of mass action:

1. Cannot be applied
2. Can be applied
3. Can be applied at low temperature
4. Can be applied at high temp. and pressure

Q. The vapor density of completely dissociated $N{H}_{4}Cl$ would be

1. same as that of $N{H}_{4}Cl$
2. double than that of $N{H}_{4}Cl$
3. half than that of $N{H}_{4}Cl$
4. slightly less than that of $N{H}_{4}Cl$

Q. The gaseous reaction : $A\left(g\right)+nB\left(g\right)\rightleftharpoons mC\left(g\right)$ is represented by the following curves
what is the value of $n+m$

Q. The gaseous reaction : $A\left(g\right)+nB\left(g\right)\rightleftharpoons mC\left(g\right)$ is represented by the following curves
what is the value of $n+m$

Q. The vapor density of completely dissociated $N{H}_{4}Cl$ would be

1. same as that of $N{H}_{4}Cl$
2. double than that of $N{H}_{4}Cl$
3. half than that of $N{H}_{4}Cl$
4. slightly less than that of $N{H}_{4}Cl$