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Fill in the blanks by putting appropriate choices. During adsorption there is _______ in enthalpy and _______ in the entropy of a system by adsorption is a spontaneous process and thus `DeltaG` must be ________. Rate of physisorption ________ with increase in pressure.

A

decrease, decrease, negative , increase

B

increase, increase , positive , decrease

C

decrease, increase, negative , decrease

D

increase, decrease, positive , increase

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The correct Answer is:
A
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Assertion : During adsorption, DeltaG, DeltaH and DeltaS decrease i.e., their values become negative. Reason : Adsorption is a spontaneous process. Randomness ofr disorder decreases during adsorption.

Work done by the system in isothermal reversible process is w_(rev.)= -2.303 nRT "log"(V_(2))/(V_(1)) . Also in case of adiabatic reversible process work done by the system is given by: w_(rev.) = (nR)/(gamma -1) [T_2 - T_1] . During expansion disorder increases and the increase in disorder is expressed in terms of change in entropy DeltaS = q_(rev.)/T . The entropy changes also occurs during transformation of one state to other end expressed as DeltaS = DeltaH/T . Both entropy and enthalpy changes obtained for a process were taken as a measure of spontaniety of process but finally it was recommended that decrease in free energy is responsible for spontaniety and DeltaG=DeltaH - T DeltaS . A chemical change will definitely be spontaneous if:

Work done by the system in isothermal reversible process is w_(rev.)= -2.303 nRT "log"(V_(2))/(V_(1)) . Also in case of adiabatic reversible process work done by the system is given by: w_(rev.) = (nR)/(gamma -1) [T_2 - T_1] . During expansion disorder increases and the increase in disorder is expressed in terms of change in entropy DeltaS = q_(rev.)/T . The entropy changes also occurs during transformation of one state to other end expressed as DeltaS = DeltaH/T . Both entropy and enthalpy changes obtained for a process were taken as a measure of spontaniety of process but finally it was recommended that decrease in free energy is responsible for spontaniety and DeltaG=DeltaH - T DeltaS . The heat of vaporisation and heat of fusion of H_2O are 540 cal//g and 80 cal//g . This ratio of (DeltaS_(vap.))/(DeltaS_("fusion")) for water is:

Work done by the system in isothermal reversible process is w_(rev.)= -2.303 nRT "log"(V_(2))/(V_(1)) . Also in case of adiabatic reversible process work done by the system is given by: w_(rev.) = (nR)/(gamma -1) [T_2 - T_1] . During expansion disorder increases and the increase in disorder is expressed in terms of change in entropy DeltaS = q_(rev.)/T . The entropy changes also occurs during transformation of one state to other end expressed as DeltaS = DeltaH/T . Both entropy and enthalpy changes obtained for a process were taken as a measure of spontaniety of process but finally it was recommended that decrease in free energy is responsible for spontaniety and DeltaG=DeltaH - T DeltaS . Which statements are correct? (1) The expansion work for a gas into a vacuum is equal to zero. (2) 1 mole of a gas occupying 3 litre volume on expanding to 15 litre at constant pressure of 1atm does expansion work 1.215 kJ . (3) The maximum work done during expansion of 16gO_2 at 300K from 5dm^3 to 25 dm^3 is 2.01 kJ . (4) The DeltaS for S to L is almost negligible in comparision to DeltaS for L to G . (5) DeltaS = 2.303 nR "log"(V_(2))/(V_(1)). (at constant T )

Work done by the system in isothermal reversible process is w_(rev.)= -2.303 nRT "log"(V_(2))/(V_(1)) . Also in case of adiabatic reversible process work done by the system is given by: w_(rev.) = (nR)/(gamma -1) [T_2 - T_1] . During expansion disorder increases and the increase in disorder is expressed in terms of change in entropy DeltaS = q_(rev.)/T . The entropy changes also occurs during transformation of one state to other end expressed as DeltaS = DeltaH/T . Both entropy and enthalpy changes obtained for a process were taken as a measure of spontaniety of process but finally it was recommended that decrease in free energy is responsible for spontaniety and DeltaG=DeltaH - T DeltaS . Ag_2O_((s)) to 2Ag_((s)) + 1/2 O_(2(g)) attains equilibrium at temperature… K is : (The DeltaH and DeltaS for the reaction are 30.5kJ mol^(-1) and 66J mol^(-1) K^(-1) )

The amount of moisture that leather adsorbs or loses is determined by temperature, relative humidity, degree of porosity, and the size of the pores. Moisture has great practical significance because its amount affects the durability of leather, and in articles such as shoes, gloves, and other garments, the comfort of the wearer. High moisture content accelerates deterioration and promotes mildew action. On the other hand, a minimum amount of moisture is required to keep leather properly lubricated and thus prevent cracking. The study indicates that adsorption of moisture by leather is a multi-molecular process and is accompanied by low enthalpies of adsorption. Further 75-percent relative humidity the adsorption is a function of surface area alone. Untanned hide and chrome-tanned leathers have the largest surface areas. The leathers tanned with the vegetable tanning materials have smaller surface areas since they are composed of less hide substance and the capillaries are reduced to smaller diameters, in some cases probably completely filled by tanning materials. This process of tanning occurs due to mutual coagulation of positively charged hide with negatively charged tanning material. The result of the study indicated that untanned hide and chrome-tanned leather adsorb the most water vapour. Assertion: Adsorption of moisture by leather is physisorption. Reason: It is a multimolecular process and is accompanied by low enthalpies of adsorption

A system of greater disorder of molecules is more probable. The disorder of molecules is reflected by the entropy of the system. A liquid vapourizes to form a more disordered gas. When a solute is present, there is additional contribution to the entropy of the liquid due to increased randomness. As the entropy of solution is higher than that of pure liquid, there is weaker tendency to form the gas. Thus, a solute (non-volatile) lowers the vapour pressure of a liquid, and hence a higher boiling point of the solution. Similarly, the greater randomness of the solution opposes the tendercy to freeze. In consequence, a lower temperature must be reached for achieving the equilibrium between the solid (frozen solvent) and the solution. The elevation in boiling point (DeltaT_(b)) and depression in freezing point (DeltaT_(f)) of a solution are the colligative properties which depend only on the concentration of particles of the solute and not their identity. For dilute solutions, (DeltaT_(b)) and (DeltaT_(f)) are proportional to the molarity of the solute in the solution. To aqueous solution of Nal , increasing amounts of solid Hgl_(2) is added. The vapour pressure of the solution

A system of greater disorder of molecules is more probable. The disorder of molecules is reflected by the entropy of the system. A liquid vapourizes to form a more disordered gas. When a solute is present, there is additional contribution to the entropy of the liquid due to increased randomness. As the entropy of solution is higher than that of pure liquid, there is weaker tendency to form the gas. Thus, a solute (non-volatile) lowers the vapour pressure of a liquid, and hence a higher boiling point of the solution. Similarly, the greater randomness of the solution opposes the tendercy to freeze. In consequence, a lower temperature must be reached for achieving the equilibrium between the solid (frozen solvent) and the solution. The elevation in boiling point (DeltaT_(b)) and depression in freezing point (DeltaT_(f)) of a solution are the colligative properties which depend only on the concentration of particles of the solute and not their identity. For dilute solutions, (DeltaT_(b)) and (DeltaT_(f)) are proportional to the molarity of the solute in the solution. A mixture of two immiscible liquids at a constant pressure of 1.0 atm boils at temperature

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