Gaseous and liquid states Questions and Answers

contained in a vessel of volume 7 litres at 0 C at 1 3 x 105 pascals 1 2 4 x 1023 3 6 x 1023 2 3 x 1023 4 4 8x1023 HTO 122

18 Gases obey vander waal s equation at 1 Only normal temperature and pressure 2 Only high temperature and high perssure 3 Only high temperature and low pressure 4 All temperature and pressure

Consider the following statements If the van der Waals parameters of two gases are given as Gas A Gas B then 1 Critical volume of A Critical volume of B 2 Critical pressure A Critical temperature of B 3 Critical temperature of A Critical temperature of B Which of the above statement is incorrect 1 1 alone 2 1 and 2 a dm bar mol 2 6 5 2 3 1 2 and 3 4 2 and 3

3 The van der Waal s constant b for N and H has the values 0 039 lit moil 1 and 0 0266 lit mo1 1 The density of solid N is 1 g cm Assuming the molecules in the solids to be close packed with the same percentage void the density of solid H would be in g cm 1 0 114 2 0 682 3 1 466 4 0 071

A general form of equation of state for gases is PV RT A where V is the molar volume of the gas and A B C are constant for the gas The values of A and B if the gas obeys van der Waals equation are respectively a 1 RT b 2 b 2a RT 3 1 b a 4 1 27b a RT

ALLEN nd is 58 Two walls of thicknesses d and d and thermal conductivity k and k are in contact In the steady state if the temperatures at the outer surface are T and T the temperature at the common wall is at of 1 K T d K T d K d K d 2 K T K T d d

80 53 Pre Medical Physics The cause of air currents from ocean to ground is 58 example of 1 The specific heat of water is more than that of sand 2 Convection

136 Pre Medical Physics 49 If a train travelling at 72 km h is to be brought to rest in a distance of 200 m then its retardation should be 20 m s 3 10 m s 1 2 2 m s 4 1 m s KN0049 55

ALLEN 41 Which of the following cylindrical rods will conduct most heat when their ends are maintained at the same steady temperature 1 Length 1 m radius 1 cm 2 Length 2 m radius 1 cm 3 Length 2 m radius 2 cm

heat heat raise its raise the by a unit IT0033 heater in is lost to ALLEN 37 The coefficient of thermal conductivity of copper is nine times that of steel In the composite cylindrical bar shown in the figure what will be the temperature at the junction of copper and steel 1 75 C 2 67 C 3 33 C 4 25 C 100 C 18cm copper 0 C steel 6cm

A body is released from the top of a tower of height Hmetres It takes t time to reach the ground Where is the body time after the release IN IT 1 Atmetres from ground 2020 metres from ground 3H 3 At H metres from the ground

Van der Waal s gas equation can be reduced to virial equation and virial equation in terms of B C If the value of critical volume is xC B Report the value of molar volume is P V Options Correct Answer 3 Solution Answer 3 At critical point dp d p dv RT 0 5 0 dv m V m V m User Answer 2

ALLEN 23 The latent heat for vapourisation for 1 g water is 536 cal Its value in Joule kg will be 1 2 25 x 10 2 2 25 x 10 28

FL0072 3 A water drop is divided into 8 equal droplets The pressure difference between inner and outer of the big drop 1 will be the same as for smaller drople SS 2 will be half of that for smaller droplet 3 will be one forth of that for smaller droplet 4 will be twice of that for smaller droplet

7 A vessel whose bottom has round holes with diameter of 0 1 mm is filled with water The maximum height to which the water can be filled without leakage is S T of water 75 dyne cm g 1000 cm s 1 100 cm 2 75 cm 3 50 cm 4 30 cm 200m MECHANICS EXBROSEP65

Water is flowing through a non uniform radius tube If ratio of the radius of entry and exit end of the pipe is 3 2 then the ratio of velocities of entring and exit liquid is 1 49 3 8 27 4 1 1 2 94

4 Steam is compressed from 1 MPa and 500 K to 5 MPa Determine the exit temperature of steam if the compression is carried out isentropically Ideal gas heat capacity C 36 0 J mol K Assume steam to follow virial gas equation of state For water Te 647 1 K Pc 220 55 bar w 0 345 Take the starting assumed isentropic exit temperature to be 725 K

46 Two water pipes P and Q having diameter 2 x 10 m and 4 x 10 m respectively are joined in series with the main supply line of water The velocity of water flowing in pipe P is 1 4 times that of Q 2 2 times that of Q

67 A sphere of mass M and radius R is falling in a viscous fluid The terminal velocity attained by the falling object will be proportional to 1 MR 2 M R 3 MR 4 M R FL0067

FL0051 2 The flow speeds of air on the lower and upper surfaces of the wing of an aeroplane are vand 2 v respectively The density of air is p and surface area of wing is A The dynamic lift on the wing is 1 pv A 2 2 pv A 3 1 2 pv A 4 2pv A

1 mole of He gas is present in a container of 12 L at 300 K If a piece of Pt metal having mass 100 g is added in the container at the 300 K and pressure of gas becomes 1 atm the mass in mg of He approx adsorbed per gram of Pt is Assume volume of Pt piece is negligible and gas is ideal Take R 0 08 atmL mol K

In a solution kept constant by buffering to pH 8 0 50 0 mL of 0 0050 M Ni2 is 0 0100 In titration with M EDTA find the pNi against the following EDTA volumes at pH 8 0 a4 5 4 10 3 a 0 00 mL b 10 0 mL c In additions of 30 00 mL EDTA

4 float completely out of water FLOO3 5 A wooden block with a coin placed on its top flox in water as shown in figure The distance a h are shown there After sometime the coin fa into the water Then coin 1 decreases and h increases 2 increases and h decreases 3 both and h increase 4 both and h decrease SS FLO

The temperature of 20 litre of Nitrogen was increased from 100 K to 300 K at a constant pressure The change in volume will be A 80 litre B 60 litre D 20 litre C 40 litre XCC

38 Select the incorrect statement about van der 78 Waal s constant b A Unit is litre mol B It depends on intermolecular forces XO It is equal to four times the actual volume of gas molecules D It is also called co volume YO C 44 A

The reaction is spontaneous at high temperatures 4 Which of the following statements is false about gases At high temperature and low pressure the ideal gas behavior is followed At high pressure the volume of the real gas is less than the ideal gas volume At low temperature and moderate pressure the attractive forces between particles are dominant At high pressure the molecular distance between gas particles approaches molecular diameter so repulsive forces are

What will be the minimum pressure required to compress 500 cm of air at 1 atm to 200 cm at 30 C X A latm C 2 5 atm B 8 2 atm D 0 4 atm X A cert of 2 1 consta occupy A 54

a 6 b Waal s constants of real gases has the units 37 The ratio of A atm mol C atm L mol a and b being the van der B L mol D atm L mol 2 A ye Ra A B

The critical constants for water are 374 C 218 atm and 0 0566 L mol Then A Van der Waal constant a 0 189 L mol B van der Waal constant b 0 0189 L mol C van der Waal constant b 2 095 L mol D At critical point z 8 3 34

Please provide a solution to this elaborating the part how changes takes place when it is taken as condensate and a fterwards Paragraph For Q No 26 to 28 The two liquids A and B have the same molecular mass and form ideal solution The solution has the vapour pressure 700 mm Hg at 80 C The above solution is distilled without reflux three fourth of the solution is collected as condensate The mole fraction of A in the condensate is 0 75 and that in the residue is 0 3 The vapour pressure of the residue at 80 C is 600 mm Hg 26 The mass ratio of A and B in the initial solution at equilibrium at 80 C was A 1 1 B 51 29 C 51 80 D 29 80 00

M The graph of P vs V is given at different temperatures and number of rule curves n n n are number of moles P V The correct relationship are a T T T c n n n T n T n T n b T T T d n n n

W gram of a fuel gas on burning gives 3 38 gm carbondioxie and 0 690 gm of water and no other product A volume of 10 0 L measured at STP of this gas weight 11 6 gm Molecular formula of fuel gas will be CH4

5 Dissociation of NH3 g on the surface of solid catalyst follows 1 Zero order reaction when concentration of NH3 is low 2 First order reaction when concentration of NH3 is high Comm www 3 Second order reaction whep concentration NH3 is high 4 Zero order reaction when concentration of segunda NH is high Devision

Which is incorrect Only one correct answer A SbH3 AsH PH3 Boiling point B C D BiH3 SbH3 ASH3 PH3 Reducing character PH3 ASH3 SbH3 NH3 BiH3 Volatility NH3 PH3 ASH3 SbH3 HEH angle

If 10 dm of water is introduced into a 1 0 dm flask to 300 K how many moles of water are in the vapour phase when equilibrium is established Given Vapour pressure of H O at 300 K is 3170 Pa R 8 314 J K mol 1 5 56 x 10 mol 3 4 46 x 10 2 mol 2 1 53 x 10 2 mol L 4 1 27 x 10 mol ygen are mixed in an empty container at 25 C The fraction of MAINS 2010

For the equilibrium LiCl 3NH3 s LiCl NH3 s 2NH3 g Kp 9 atm at 310 K A 5 L vessel contains 0 1 mole of LiCl NH3 How many mole of NH3 should be added to the flask at this temperature derive the backward reaction for completion use R 0 082 atm L mol K Report your answer upto two decimal

A solution is prepared by mixing 100 mL each of CH OH d 0 8 g mL and C H OH d 1 g mL If M is molarity of solution having CH OH solute in C H OH solvent and M is molarity of solution having C H OH solute in CH OH solvent Then 1 M M M 2 M M 4 M M 50

138 What is the entropy change in J K during the melting of 27 3 grams of ice at 0 C Latent heat of fusion of ice 330 J g 27 3 0 0 C 3 58A 50 8555 53 1 330 3 3 3 or J K 5 0 330 J g 2 4 12 1 33

23 The pressure P of an ideal diatomic gas varies with its absolute temperature T as shown in figure The molar heat capacity of gas during this process is R is gas constant P 1 1 7 R 2 3 25 R 3 2 5 R T

Board Competitive Exams 20 AP T graph is shown for a cyclic process Select correct statement regarding this JA D 1 During process CD work done by gas is negative 2 During process AB work done by the gas is positive 24 A P 1 2 4 25 TI id fig pe

A solution contains 5 moles of X and 5 moles of Y and has a normal boiling point of 90 C The vapor pressure of pure X is 300 mm Hg What is the vapor pressure of pure Y at this temperature 5ar6 X5053 5 Yoo bado o 90 C 6 X 300 mm Hg use og Yerbau Jod Options 3 1220 atm 1220 Tom 1220 N m 1220 bar Question Number 144 Question Id 7512365584 Question Type MCQ Option Shuffling Yes Display Question Number Yes Single Line Question Option No Option Orientation Vertical Consider the following equilibrium for benzoic acid in benzene 2CH COOH C H COOH If x represents the degree of association of the solute then relationship between total number of moles of particles at equilibrium and van t Hoff factor 1 is Bod ous de Bode Bob Serpen Kodo C H COOH de esa cousand sehe so ugo sare 3rd Songs 2C H COOH da paso Jos ass 1 Sodg Soodu

2 3 Both statements are correct bode 356m 30055 Question Number 127 Question 14 7512365567 Question Type MCQ Option Shuffling Yes Display Question Number Yes Single Line Question Option No Option Orientation Vertical Aclosed container has 1 Avogadro mmber of gaseous molecules at 27 C and 1 atm pressure The pressure of the same gas at 72 C in atm is 27 C So I atm baso se 1 sm Song to Jaw umyw as Subay de anjo e Jo 72 C 5 5555 atm 6 Options 2 30 0 87 3 17 1 15

A closed container with a fine hole contains a mixture of hydrogen and oxygen gases at 2 atm pressure The mixture contains 4 hydrogen by weight Calculate the ratio of rates of effusion of two gases 1 3 8 2 8 3 3 2 5 4 3 2

Two moles of a gas at temperature T and volume V are heated to twice its volume at constant pressure Ify then increase in internal energy of the gas is 1 3 RT Y 1 2RT 3 1 1 2 E 2RT Y 1 2T Y 1

31 An equilibrium PC15 g PC13 g Cl2 g is obtained by starting with 1 mol of PC15 in a 1 L vessel A vapour density of equilibrium mixture was found to be 250 2 Now the equilibrium mixture is transferred into a vessel of 2 L capacity its new degree of dissociation is

P Two gas bulbs A and B are connected by a tube having a stopcock Bulb A has a volume of 100 ml and contains hydrogen After opening the gas from A to the evacuated bulb B the pressure falls down by 40 The volume mL of B must be 1 75 2 150 3 125 4 200

1 If the distribution of molecular speeds of a gas is as per the figure shown below then the ratio of the most probable the average and the roots mean square speeds respectively is A 1 1 1 C 11 128 1 224 Fraction of molecules A speed B 1 1 1 224 D 1 1 128 1 Ans B Sol Graph represents symmetrical distribution of speed and hence the most probable and the average speed should be same But the root mean square speed must be greater than the average speed

Consider a 70 efficient hydrogen oxygen 298 K Its cell reaction is fuel cell working under standard conditions at 1 bar an 1 H g O g H 0 1 The work derived from the cell on the consumption of 1 0 x 10 3 mol of H g is used to compres 1 00 mol of a monoatomic ideal gas in a thermally insulated container What is the change in th emperature in K of the ideal gas The standard reduction potentials for the two half cells are given below O g 4H aq 4e 2 H 0 1 E 1 23 V 2H aq 2e H g E 0 00 V Use F 96500 C mol 1 R 83141 mol 1 K 1

If the distribution of molecular speeds of a gas is as per the figure shown below then the ratio of the most probable the average and the root mean square speeds respectively is A 1 1 1 C 1 1 128 1 224 Fraction of molecules speed B 1 1 1 224 D 1 1 128 1

The K of Ag2CrO4 AgCl AgBr and Ag will precipitate last if AgNO3 solution is added to 13 8 3 x 10 17 Which one of the following salts respectively 1 1 x 10 12 1 8 x 10 10 5 0 10 the solution containing equal moles of NaCl NaBr 1 AgCl 3 Ag CrO4 2 AgBr 4 Agl