Question

i need help with #s 30-32 and can you check 28 and 29

28. Which of the following is an isomer of CHOCH,? (a) CH.CH (b) CH,COOH (C) CH,CH,OH (4) CH,CH,CH, c) CH-CH,O CHỊCH, at atm? an a 29. Which of the following has the greatest solubility in C. H (a) SO (b) NaCl H.O. (d) CCIO JOT NH H - c-c- c-c-c- HHH 30. High solubility of an ionic solid in water is favored by which of the following conditions? I. The existence of strong ionic attractions in the crystal lattice. II. The formation of strong ion-dipole attractions. III. An increase in entropy upon dissolving. (a) I only (b) I and II only (c) I and III only (d) II and III only (e) I, II, III 31. Which of the following statements is true for the equilibrium vapor pressure of a liquid in a closed system? (a) It remains constant when the temperature increases. (b) It decreases to half its original value if the volume of the gas phase is doubled. (c) It increases to twice its original value if the volume of the liquid phase is doubled. (d) It decreases to half its original value if the surface area of the liquid is reduced by one-half. (e) It is independent of the volume of the vapor phase. 32. A molecular solid coexists with its liquid phase at its melting point. The solid-liquid mixture is heated, but the temperature does not change while the solid is melting. The best explanation for this phenomenon is that the heat absorbed by the mixture (a) is lost to the surroundings very quickly (b) is used in overcoming the intermolecular attractions in the solid (c) is used in breaking the bonds within the molecules of the solid. (d) causes the nonbonding electrons in the molecules to move to lower energy levels. (e) causes evaporation of the liquid, which has a cooling effect.

Answer 1

30.. solubility of ionic compounds depends upon the hydration en thalpy. Greater the ionic nature greater will be energy Lbydration enthalpy) released (exothermic), more will be solubbility Also as ionic nature increases, its polarity increases. we know polar solute dissoue in polar solvent. So, on increasing ionic nature, its solubility in ware Increases. • Solubility is the result of hydration ie individual cation and Vanion gets hydrated by water molecule.

This hydrated ions form lon-dipole interaction. Thus greater the ion di pole interaction, more will be solubility. · On dissolving the ionic solid in water, the individeeal ellions and anions get freed up and able to move more freely as compared in closed packed Crystal solid, resulting in increase in entropy. | Answer-Option @ 31. . vapour pressure can be considered as a reaction between liquid and vapour phase as per following – H₂O (1) H2O(g), k The concentrarion of each component depends upon K., and this equilibolum constantak depends upon temperature As temperature increases, equilibrium constant increases o and thus vapour pressure also increases. Moow we know that concentration of pure liquid renaine e constant. So at constant temperature, we have valves of [H20 (1) J and K constant (fixed), which makes value of [H2019)] constant die making vapour pressure constant. • Even if we change ladd) remove some Liquid / vapour entide cloved container , equilibrium will reach so that a to make vapour pressure constant. • Also Pressure is the extensive property, it does not depend upon the size of the sample

Increasing / decreasing the sterface surface area will only help to attain the equilibrium faster/scower and will not alter the vapour pressure. lie. a container will larger surface area will attain equilibrium early as compared to one with smaller surface area. | Answer-Option - [32 ] H2013) healing H2011), AH fusion. lice) (reating) (water, when we heat up ice, the energy supplied is used to break the intermolecular attractions ( more specifically hydrogen bonds) in the solid , so that H2O molecules are free to move ice. convert into liquid phase. Answer-option ®