Difficult
Describe the method for measuring the equilibrium vapour pressure of water at a constant temperature.
(N/A) Process: Consider a transparent box equipped with a $U$-tube manometer containing mercury. $A$ drying agent,such as anhydrous calcium chloride $(CaCl_2)$ or phosphorus pentoxide $(P_4O_{10})$,is placed in the box for a few hours. This ensures the air inside the box is free from moisture (vapour).
After removing the drying agent by tilting the box,a watch glass (or petri dish) containing water is quickly placed inside the box.
Observation: The mercury level in the right limb of the manometer will be observed to increase slowly and eventually attain a constant value.
Conclusion: The observation indicates that:
$(i)$ Initially,the pressure inside the box increases due to the evaporation of water.
$(ii)$ After some time,the pressure inside the box becomes constant,indicating that the rate of evaporation equals the rate of condensation (equilibrium state).
$(iii)$ The volume of water in the watch glass decreases slightly until equilibrium is reached.
After removing the drying agent by tilting the box,a watch glass (or petri dish) containing water is quickly placed inside the box.
Observation: The mercury level in the right limb of the manometer will be observed to increase slowly and eventually attain a constant value.
Conclusion: The observation indicates that:
$(i)$ Initially,the pressure inside the box increases due to the evaporation of water.
$(ii)$ After some time,the pressure inside the box becomes constant,indicating that the rate of evaporation equals the rate of condensation (equilibrium state).
$(iii)$ The volume of water in the watch glass decreases slightly until equilibrium is reached.
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$A$ chemical reaction is at equilibrium when
Explain the types of physical equilibrium with examples.
Difficult
View SolutionPredict which of the following reactions will have an appreciable concentration of both reactants and products:
$(a)$ $Cl_{2(g)} \longleftrightarrow 2Cl_{(g)};$ $K_{c}=5 \times 10^{-39}$
$(b)$ $Cl_{2(g)}+2NO_{(g)} \longleftrightarrow 2NOCl_{(g)};$ $K_{c}=3.7 \times 10^{8}$
$(c)$ $Cl_{2(g)}+2NO_{2(g)} \longleftrightarrow 2NO_{2}Cl_{(g)};$ $K_{c}=1.8$
$(a)$ $Cl_{2(g)} \longleftrightarrow 2Cl_{(g)};$ $K_{c}=5 \times 10^{-39}$
$(b)$ $Cl_{2(g)}+2NO_{(g)} \longleftrightarrow 2NOCl_{(g)};$ $K_{c}=3.7 \times 10^{8}$
$(c)$ $Cl_{2(g)}+2NO_{2(g)} \longleftrightarrow 2NO_{2}Cl_{(g)};$ $K_{c}=1.8$
Medium
View SolutionWhen two reactants $A$ and $B$ are mixed to form products $C$ and $D$,what is the value of the reaction quotient $Q$ at the initial state of the reaction?
Easy
View SolutionThe equilibrium constant for the reaction $N_{2(g)} + O_{2(g)} \rightleftharpoons 2NO_{(g)}$ is $4 \times 10^{-4}$ at $2000 \ K$. In the presence of a catalyst,the equilibrium is attained ten times faster. Therefore,the equilibrium constant in the presence of a catalyst at $2000 \ K$ is:
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