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51
In jet refrigerators, the refrigerating fluid is practically always
Discuss
Answer & Solution
Answer: Option A
Solution:
Water is generally used as a refrigerant fluid in jet refrigerators.
52
In the reaction; N2 + O2 ⇋ 2NO, increasing the pressure will result in
Discuss
Answer & Solution
Answer: Option C
Solution:
According to Le Chatelier's principle when we apply high pressure the system will react in such a way that it counters the effect of increasing pressure so, the system has to shift the equilibrium towards less number of moles side(thereby, decreasing the volume) and thus opposing the effect. But in the given reaction the numbers of moles are same in both reactants and products side so, the tendency to shift the equilibrium towards products side and reactants side become equal and thus showing no effect on equilibrium.
53
Number of degrees of freedom for a three phase system in equilibrium comprising of three non-reacting chemical species is
Discuss
Answer & Solution
Answer: Option A
Solution:
Given, number of phases $$\left( \emptyset \right) = 3$$
Number of non-reacting components $$= 3$$
So, degree of freedom $$ = C - \emptyset + 2 = 3 - 3 + 2 = 2$$
54
Gibbs-Duhem equation relates composition in liquid phase and the __________ at constant temperature & pressure.
Discuss
Answer & Solution
Answer: Option D
Solution:
The Gibbs–Duhem equation is given as $$\sum {} _{i\, = \,1}^n\,\,{n_i}d{\mu _i} = + vdP - sdT$$     at constant temperature and pressure it simply becomes $$\sum {} _{i\, = \,1}^n\,\,{n_i}d{\mu _i} = 0,$$    which tells us that the chemical potential of an specie is not entirely independent on chemical potential of other species and also relates chemical potential with composition if we write this in terms of fugacity and activity co-efficients it will relate them with composition to.
55
For multicomponent multiple phases to be in equilibrium at the same pressure and temperature, the __________ of each component must be same in all phases.
Discuss
Answer & Solution
Answer: Option C
Solution:
Both the chemical potential and fugacity must be same in all the phases to attain thermodynamic equilibrium. Actually, the calculation of chemical potential and visualizing it physically is slightly tedious so, we introduced the concept of fugacity which is easy to visualize and we have also many correlations to measure it so, the origin of fugacity taken place. And we related the chemical potential with it as following:
$${\mu _i} = RTdln{f_i}$$
So, the equality of chemical potential will result in equality of fugacity also between the phases.
56
Chemical potential (an intensive property) of a substance is a force that drives the chemical system to equilibrium and is equal to its partial molar properties. The reatio of chemical potential to free energy of a pure substance at oconstant temperature and pressure is
Discuss
Answer & Solution
Answer: Option B
Solution:
The chemical potential is nothing but partial molar gibbs free energy (since the partial molar functions depicted the change in total molar property with change in composition(moles) we consider partial molar functions as intensive properties), $${\mu _i} = \left( {\frac{{\partial nG}}{{\partial {n_i}}}} \right)T,P,{n_j}$$     when there is only one component ,G(total molar gibbs free energy) becomes independent of composition(intensive property ) so the equation becomes $${\mu _i} = G\left( {\frac{{\partial {n_I}}}{{\partial {n_i}}}} \right)T,P,{n_j}$$
Hence, $${\mu _i} = G$$
57
One ton of refrigeration capacity is equivalent to the heat removal rate of
Discuss
Answer & Solution
Answer: Option C
Solution:
One ton of refrigeration is defined as the amount of heat to be extracted from one ton of water at $${0^ \circ }C$$   to convert it to one ton of ice at $${0^ \circ }C.$$  Which is equivalent to heat removal of $$200\,BTU/\min .$$
58
Internal energy of an ideal gas
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Answer & Solution
Answer: Option D
Solution:
Internal energy of an ideal gas is solely dependent on temperature and given by the relation: The internal energy of an substance is given by
$$\eqalign{ & dU = CvdT - \left[ {P + T\left( {\frac{{\left( {\frac{{\partial V}}{{\partial T}}} \right)p}}{{\left( {\frac{{\partial V}}{{\partial P}}} \right)T}}} \right)dV} \right] \cr & {\text{For an ideal gas, }}PV = RT \cr & {\text{So, }}\left( {\frac{{\partial V}}{{\partial T}}} \right)p = \frac{R}{P}\,\,{\text{and }}\left( {\frac{{\partial V}}{{\partial P}}} \right)T = - \frac{{RT}}{{{P^2}}} \cr & {\text{Hence, }}dU = CvdT \cr} $$
So internal energy is only a function of temperature and increases with increase in temperature.
59
In an ideal refrigeration cycle, the change in internal energy of the fluid is
Discuss
Answer & Solution
Answer: Option C
No explanation is given for this question. Let's Discuss on Board
60
In a reversible chemical reaction (where, Δx = number of moles of products-number of moles of reactants )
Discuss
Answer & Solution
Answer: Option D
Solution:
All the given statements are correct. According to Le Chatelier's principle when we apply high pressure the system will react in such a way that it counters the effect of increasing pressure so, the system has to shift the equilibrium towards less number of moles side(thereby, decreasing the volume) and thus opposing the effect. But in the given reaction the numbers of moles are same in both reactants and products side so, the tendency to shift the equilibrium towards products side and reactants side become equal and thus showing no effect on equilibrium.