Gaseous and liquid states Questions and Answers

What is the variation of Z with pressure a At very low pressures all gases show Z 1 At high pressures all gases show Z 1 b c At intermediate pressures most gases show Z 1 d All of the above

A 100 0g ice cube at 0 0 C is placed in 650 of water at 25 C what is the final temperature of the mixture 1 11 C 2 12 5 C 3 18 C 4 16 C

Volume of the flask in which species are transferred is double of the earlier flask In which of the following cases equilibrium is affected 2 Ens LO I N g 3H g 2NH g HO II N g O g 2NO g III PC1 g PC1 g Cl g HO IV 2NO g N g O g 1 I II 2 II III 3 I III 1 4 III IV

An open vessel at 27 C is heated until 3 5 parts of air in it has been expelled Assuming that the volume of the vessel remains constant find the temperature to which the vesel had been heated Ans 750K

A sample of a hydrate of barium chloride weighing 61 g was heated until all the water of hydration is removed The dried sample weighed 52 g The formula of the hydrated salt is atomic mass Ba 137 amu Cl 35 5 amu 1 BaCl H O 2 BaCl 2H O 3 BaCl 3H O 4 BaCl 4H O

For the reaction N g 3H g 2NH g Heat of reaction at constant volume exceeds the heat of reaction at constant pressure by XRT The value of x is

41 The molal boiling point constant for water is 0 513 C kg mol When 0 1 mole of sugar is dissolved in 200 ml of water the solution boils under a pressure of one atmosphere at 2011 a 100 513 C c 100 256 C b 100 0513 C d 101 025 C

The temperature at which intermolecular attraction force balance the intermolecular repulsion force is known as 1 Boyle temperature in 2 Critical temperature 3 Boiling temperature 4 Equilibrium temperature

5 A mixture of SO and O in the molar ratio 16 1 is diffused through a pin hole for successive effusions three times to give a molar ratio 1 1 of diffused mixture Which one are not correct if diffusion is made at same P and T in each operation I Eight operation are needed to get 1 1 molar ratio II Rate of diffusion for SO O after eight operations in and 0 707 III Six operations are needed to get 2 1 molar ratio for SO and O in diffusion mixture IV Rate of diffusion for SO and O after six operations is 2 41 1 I II III 3 I III 2 II III 4 IV

1 The average molar heat capacities of ice and water are 37 6 and 75 2 J mol K respectively and its enthalpy of fusion is 6 02 kJ mol The amount of heat required to raise the temperature 0 moter DOT of 10 g of water from 10 C to 10 C is equal to a 2376 Jb b 4752 Jo c 1128 Jd d 3970 JES

1 200 mL of hydrogen and 250 mL of nitrogen each measured at 15 C and 760 mm pressure are put together in a 500 ml flask What will be the final pressure of the mixture at 15 C 100 ml of N gas at 700 mm and 300 ml of H gas at 800 mm were introduced into a vessel of 2 litres at

a where V is the molar volume of the gas and a b The equation of state for a real gas is P are constants different than Vanderwaal s constant then calculate the temperature at which the gas follows RT V b TV boyle s law at low pressure A a Rb 8a B 27Rb C a Rb D 8a RT TU 1 a v

64 A gas is found to contain 2 34 g of Nitrogen 5 34 g of oxygen Simplest formula of compound is 1 N O 2 NO 3 N O 4 NO 2

17 0 75 mole solid A4 and 2 mole O are heated in a sealed bulb to react completely and producing one mole of compound If product formed is also i gaseous state predict the ratio of final pressure a 600 K to initial pressure at 300 K

When a mixture of NaCl and NaBr is heated with H SO4 the halogen components are liberated as their hydracids leaving Na SO4 as the residue In an experiment the mass of Na SO4 left is equal to the mass of NaCl NaBr taken at the begining of the experiment Calculate the percentages of NaCl and NaBr in the given mixture

20 mL of methane is completely burnt using 50 mL of oxygen The volume of the gas left after cooling to room temperature is 1 80 mL 2 40 mL 3 60 mL 4 30 mL

Problem 10 2 At 300 K a certain mass of a gas ocupies 1 104 dm volume Calculate its volume at 450 K and at the same pressure

13 A real gas obey Berthelot equation of gas that is pola P 1 The Boyle s temperature for this is a and b are constant Tower TV Vm b RT Rb 2a 3 Rb 2 4 a VRb 2a VRb

5 An ideal gas is is collected by downward displacement of according to water Selcet the correct expression for P the diagram dHg 13 6 g cm gas Gas 1 P gas 2 P gas h cm H O d 1 g cm Patm aq Tension h 13 6 Patm hdg 3 P Patmaq Tension h 13 6 gas 4 None of these

a 80 cc 10 gm of a gas at 1 atm and 273 K occupies 5 litres The temperature at which the volume becomes double for the same mass of gas at the same pressure is 273 K b 273 C c 273 C d 546 C

1 Surface tension does not vary with b concentration a temperature e size of the surface d vapour pressure

olarity of gm of pure water Mo 1 40M 2 4M 3 55 5M 4 Can t be determined

25 0 ml of an iron III solution of unknown concentration were titrated against the standard 0 5M VOSO 2H O solution The average titre value of VO2 ion needed to completely react with the solution containing the Festions was 22 14 ml The mass of VOSO 2H O Mol wt 199 required to make 250 ml of the standard solution is C 12 45 gm D 100 gm A 24 9 gm B 49 8 gm

2 Which is correct for gases showing attraction behaviour 1 3 dV dPr T 0 d PV dP T 0 2 d dP PV 0 T 4 All of these

Thomas Andrews plotted the P V curve for CO2 He plotted the isotherms of CO at various temperatures Later on it was found that real gases behave in the same manner as CO2 Andrews noticed that at high temp isotherms look like that of an ideal gas and cannot be liquified even at very high pressure As temp is lowered shape of curve changes from ideal behaviour 1 Sol 2 Sol P 70 C 50 C 30 C 20 C 13 C V The critical temp of gases A B C and D are 126 K 154 3 K 304 15 K 405 K respectively which gas shown greater deviation from ideal behaviour with increase in pressure A A C C B B D D D The compressibility factor of a van der Waal s gas at its critical point is A 1 B 0 375 C 2 67 D 0 48 B

Dipole dipole forces act between the molecule possessing permanent dipole Ends of dipole possess partial charges The partial charge is a more than unit electronic charge b equal to unit electronic charge c less than unit electronic charge d double the unit electronic charge

Starting with 3 1 mixture of H and N at 450 C the equilibrium mixture is found to be 9 6 NH 22 6 N and 67 8 H by volume The total pressure is 50 atm What will be the value of K The reaction is 3H 2NH3 N A 3 25 105 atm 2 2 B 5 23 x 105 atm 2 C 6 23 x 105 atm D 8 10 atm

1 If P and Pg are 108 and 36 torr respectively What will be the mole fraction of A is vapour phase if B has mole fraction in solution 0 5 1 0 25 3 0 60 2 0 75 4 0 35

8 What produces more severe burns boiling water or steam 9 Name A B C D E and F in the following diagram showing chang in its state

Identify the incorrect statement s a selected The ratio of the observed molar volume to ideal molar volume is called compressibility factor Z The value of van der Waals constants a and b is independent of the nature of gas At low temperature and high pressure the behaviour of any gas is explained by PV nRT ility factor 7 1 For He gas 273 K

52 Which of the following graph is correct for a real gas below its critical temperature 1 3 P V 2 P 4 V V

5 g of an unknown gas at 27 C and 0 2 g gas at 47 C have same volume at dihydrogen atmospheric pressure The molecular mass of the unknown gas is 1 46 8 3 46 7 2 42 6 4 50 2

6 Some relations of Cp and Cy for an ideal gas

A mixture containing N and H in a mole ratio 1 3 is allowed to attain equilibrium when 50 of the mixture has reacted If P is the pressure at equilibrium then the partial pressure of NH3 formed is A P 2 C P 5 B P 3 D P 9

0 8 18 If 10 g of an unknown substance non electrolyic is dissolved to make 500 mL of solm 300 K is observed to be 1 23 atm find m wt

4 56 1 dm solution containing 105 moles each of Cl ions and CrO2 ions is treated with 10 4 moles of silver nitrate Which one of the following observations is made Ksp Ag 2CrO4 4 10 Ksp AgCl 1x 10 101 a Precipitation does not occur b Silver chromate gets precipitated first c Silver chloride gets precipitated first d Both silver chromate and silver chloride

1 mol of a non ideal gas undergoes the given change 2 atm 3 L 95 K 4 atm 5 L 245 K In this process if increase in internal energy of the gas is 30 L atm then what will be its change in enthalpy s The change in enthalpy AH A U PV AU A PV AU P V2 P1V Given AU 30 L atm P 2 atm P 4 atm 3L and V 5 L AH 30 4x5 2 x 3 L atm 441 atm

If 20 ml of 0 5 M Na SO is mixed with 50 ml of 0 2 M H SO4 30 ml of 0 4 M Al SO4 3 solution Calculate Na H SO 2 A1 Assuming 100 dissociation moles

gas X is present with saturated water vapour over water liquid at total pressure of 1 5 atm Vapou essure of H O at same temperature is 0 5 atm What is the solubility of gas X in terms of mole 10 moles H O Partial pressure of X slope 38x10 torr mol frac of x in H O

3 Assuming the same pressure in each case calculate the mass of hydrogen required to inflate a balloon to a certain volume V at 100 C if 3 5 g helium is required to inflate the balloon to half the volume V at 25 C

998 2 One way of writing the equation of state for real gases where B is a constant is PV RT 1 B V 3 Derive an approximate expression for B in terms of van der Waals constants a and b IIT May 19971

46 A metal X crystallises in a face centred cubi arrangement with the edge length 862 pm What is the shortest separation of any two nuclei of the atom b 707 pm d 609 6 pm a 406 pm c 862 pm

When a vander waal s gas undergoes free expansion then it MP PET 2009 temperature a Decreases b Increases c Does not change d Depends upon the nature of the gas

The ratio of activities of two ratio nuclides X and Y in a mixture at time t 0 was found to be 4 1 After two hours the ratio of activities become 1 1 If the t1 2 of ratio nuclide X is 20 min then t 2 in minutes of ratio nuclide Y is

9 H O restores the colour of old lead paintings blackened by the action of H S gas by 1 Converting PbO to Pb 2 Oxidising PbS to PbSO 3 Converting PbCO3 to Pb 4 Oxidising PbSO to PbSO

D Henry law constant of N in water is 104 atm Find the molality Approx of N in water when pressure of N over water surface is 5 atm consider 2 temperature remains constant 1 0 10 2 0 028 3 0 05 4 0 12

1 a A mixture of hydrogen and oxygen at one bar pressure contains 20 by weight of hydrogen Calculate the partial pressure of hydrogen b A sample of gaseous arsine AsH3 in a 500 mL flask at 300 torr and 223 K is heated to 473 K at which AsH3 decomposes to solid arsenic and H gas The flask is then cooled to 273 K at which the pressure in flask is 508 torr Calculate the of ASH decomposed

5 A student forgot to add the reaction mixture to the round bottomed open flask at 27 C and put it on the flame After a lapse of time he realized his mistake using a pyrometer he found the temperature of the flask was 477 C What fraction of air would have been expelled out

3 The behaviour of a real gas is usually depicted plotting compressibility factor Z versus P at a consta temperature At high temperature and high pressur Z is usually more than one This fact can be explain by van der Waals equation when a The constant a is negligible and not b b The constant b is negligible and not a c Both the constants a and bare negligible d Roth

3 Pressure of the gas in column 1 is A 60 cm of Hg 60 B 55 cm of Hg 20 cmp 6 8 g ml of liquid x 20 cm Hg P 75 of Hg C 50 cm of Hg D 45 cm of Hg