Equilibrium Questions and Answers

126 For an equilibrium 2A g B g 3C s at equilibrium A 4 B When A was added in th next equilibrium moles of A becomes 4 times the initi equilibrium What will be the new concentration of relative to its initial concentration 1 3 4 2 4 8

A solid substance x dicompose into two gasesous products y and z as x s 2y g z g If at equilibrium some z g at 1 atm is added in constant volume condition 10 of y g solidified before the equ was re establised Determine total pressure in bar at final equilibrium

Physical Chemistry Q14 50 ml of M 10 acetic acid is mixed with the 100 ml of M 10 KOH solution then the resultant solution is added to the mixture of 25 ml N 10 sulphuric acid and 25 ml of M 10 sodium hydroxide solution Then the pH of the resulting mixture is approximately O 1 6 O 12 4 07 None

c 2 5 1 54 The reaction C H g C H g H g is at equilibrium in a closed vessel at 1000 K The enthalpy change AH for the reaction is 137 0 kJ mol Which one of the following actions would shift the equilibrium to the right a Decreasing the volume of the closed reaction vessel b Decreasing the temperature at which the reaction is performed c Adding an inert gas to the closed reaction vessel d Increasing the volume of the closed reaction vessel

Select the incorrect statement at equilibrium O Equilibrium is possible in closed system on O Both the opposing processes occur at the same rate O Concentration of reactants always become equal to the concentration of products O All measurable properties of the system remain constant

Following equilibrium is present in a closed container at the temperature of 25 C SO Cl g SO g Cl g 1 1 p When Cl is added to the equlibrium mixture the following statements will be correct for the system a Concentrations of SO2 Cl and SO Cl change b Cl is formed in more amount 2 c Concentration of SO decreases and that a SO Cl increases HAS 1 a c 2 a bodround na 3 b

The equilibrium constant K for the following reaction at 1650 C is 4 2 Initially 0 80 mol of CO and 0 80 mol of H are injected into a 5 0 L flask Calculate the concentration of each species at equilibrium 15 pts CO g H O g CO H g

Given Bond Energy in kJ mol 85 Bond Bond Energy 435 Enthalpy of vaporisation of H O 52 kJ mol The enthalpy of formation of H O is in kJ mol O 47 H H 189 0 0 498 O H 464 0 0 142

What is the value of the equilibrium constant Kc for the following reaction at the temperature of the mixture 2NO g N 04 8 Analyses of an equilibrium mixture of N O4 g and NO g gave the following results NO g 4 726x10 M

Equilibrium constant expression for the equilibrium CO g 3 H g CH4 g H O g is O O CO 3H CH4 H O O CH4 H O CO 3H O ICO H2 3 CH H O CH4 H O CO H2 3

a ALLEN certain reaction if no effect on equilibrium is 73 may seen on addition of inert gas then situation be 1 constant temperature constant pressure for An 0 reactions constant temperature constant pressure for Ang 0 reactions 3 constant temperature constant volume for Ang 0 reactions 4 both 2 3

A weak acid is titrated against a strong base and the volume of titrant added is plotted against pH as shown below pH 10 8 4 Which of the following statements regarding above titration is correct 1 The substance in beaker is a solution of weak tri basic acid

2CO g 2CO g O g the dissociation of 2 moles of CO is carried out in container with volume 5 L If at equilibrium 60 CO dissociated then number of moles at equilibrium will be 1 2 3 2 26 3 3 0 4 3 2

e plasma methotrexate is 9 ng mL at 10 00 At 12 00 the methotrexate concentration is 7 ng mL What is the half life for methotrexate in this patient h 2 hr 5 5 O The result is invalid O

If for the equilibrium PCI g PCl3 g Cl g 1 mola PCI5 is present initially and at equilibrium 0 6 M Cl is formed than the value of Kc for the given reaction is O O O 10 F 10 10 11 90

Which of the following is correct regarding the gas solution equilibrium 1 The solubility of the dissolved gas incr ases with the increase of pressure and decreases with the increase c temperature 2 The solubility of the dissolved gas increases with the increase of pressure as well as temperature 3 The solubility of the dissolved gas decreases with the increase of pressure and increases with the increase c temperature 4 The solubility of the dissolved gas decreases with the increase of pressure as well as temperature

Two systems PCI g PCl3 g Cl g and COCI g CO g Cl g are simultaneously in equilibrium in a vessel at constant volume If some CO g is introduced in the vessel at constant volume then at new equilibrium the concentration of 1 PC is increases 2 PCI remains unchanged 3 PCI is decreases 4 CL in ingroaco

M Catalyst Package for NEET Pan 38 The variation of K with T was studied by plotting 1 logk with AH of reaction is T log K 11T 545 2 2 cal 4 4 606 cal 1 2 cal 3 4 606 cal P 39 The pH of 10 10 M NaOH solution is 1 7 2 Slightly less than 7 3 Slightly greater than 7 4 10

Cis 2 pentene Trans 2 pentene for th above equilibrium the value of standard free energ change at 400 K is 3 67 kJ mol If excess trans 2 pentene is added to the system then 1 Additional trans 2 pentene will form 2 Excess of cis 2 pentene will form 3 Equilibrium will proceed in the forward 1 Equilibrium will remain unaffected

14 2 The precipitate of CaF Ksp 1 7 x 10 10 is obtained when equal volumes of the following are mixed 1 10 4 M Ca2 10 4 MF 2 10 2 M Ca 10 3 MF 3 10 5 M Ca 10 3 MF 4 10 3 M Ca2 10 5 MF 3x102 SOO XT

5 For the reaction Steps are I NO g F g NO F g Fast K K2 2NO g F g k3 II NO F g NO F g F g Slow K4 III F g NO g NO F g Fast 2NO F g Select the correct statement s a Rate law is in agreement with net stoichiometry of the reaction b Rate law is in agreement with slow step c Rate law is in agreement with net stoichiometry of the reaction as well as with s step d None of the above

8 The solubility product of Cr OH at 298 K is 6 0 x 10 1 The concentration of hydroxide ions in a saturated solution of Cr OH will be 1 18 10 31 1 4 3 18 10 31 2 X 2 4 86 x 10 29 1 4 4 2 22 x 10 3114

106 What is the pH of a solution obtained by dissolving 0 0005 mole of the strong electrolyte calcium hydroxide Ca OH to form 100 ml of a saturated solution aqueous AFMC K 1 0 10 4 mole litre 2 1 9 8 2 11 7 3 12 0 4 3 0

Consider the following reversible reaction at a particular temperature N g 3H g 2NH g for which the equilibrium constants in terms of mole fraction x and partial pressure p are defined as 2 XNH Kx 3 XN XH and Kp 2 PNH3 3 PN PH respectively Let an equilibrium mixture contain 3 mol of H 1 mol of N and 1 mol of NH3 Now keeping the temperature constant 1 mol of inert gas is added at constant volume then select correct statement

Let the solubilities of AgCl in H O 0 01M CaCl 0 01M NaCl and 0 05M AgNO3 be S S2 S3 S4 respectively What is the correct relationship between quantities 1 2 3 4 ect Answer 2 S1 S2 S3 S4 1 3 2 S4 4 S2 S3 S1 4 S3 2 S1

A reversible reaction has a Gibbs free energy that is positive under standard conditions Which of the following is true about this reaction O The equilibrium constant for this reaction is between zero and one O The Gibbs free energy for this reaction will be positive under all conditions O The equilibrium constant for this reaction is negative O The equilibrium constant for this reaction is greater than one O The reaction has no equilibrium constant

10 The table below gives the K of six acids Acid acetic acid ammonium ion chloroacetic acid A B C D Selected Values of Aqueous Acid Ionization Constants at 25 C Formula K CH3COOH 1 75 x 10 5 NH 5 60 10 10 CH CICOOH 1 36 x 10 3 HONH3 1 12 x 10 6 H S 1 02 x 10 7 hydroxylammonium ion hydrogen sulphide Which of the following combinations correctly pairs the strongest acid and the weakest acid Strongest acid H S CH CICOOH CH3COOH CH3COOH Weakest acid NH NH HONH3 H S

If 8 mol of PCl heated in a closed vessel of 10 L capacity and 25 of its dissociates into PCI and Cl at the equilibrium then value of Kp will be equal to P is total puerime at eam ed of bruc 1 P 30 2 P 15 3 2 3P 4 3 2P

Synthesis gas is a mixture of carbon monoxide and water vapor At high temperature synthesis gas will form carbon dioxide and hydrogen and in fact this reaction is one of the ways hydrogen is made industrially A chemical engineer studying this reaction fills a 200 mL flask with 4 3 atm of carbon monoxide gas and 1 3 atm of water vapor When the mixture has come to equilibrium he determines that it contains 3 83 atm of carbon monoxide gas 0 83 atm of water vapor and 0 47 atm of carbon dioxide The engineer then adds another 1 4 atm of carbon monoxide and allows the mixture to come to equilibrium again Calculate the pressure of hydrogen after equilibrium is reached the second time Round your answer to 2 significant digits

An acid base indicator has K 3 x 10 5 The acid form of the indicator is red and the basic form is blue By how much must the pH change in order to change the indicator from 75 red to 75 blue log 3 0 4770 A 0 65 B 1 3 C 0 954 Correct Answer C

The pH of pure water at a given temperature is 6 8 If 100 mL of 0 02 M HC1 and 100 m of 0 02 M NH OH are mixed at that temperature the pH of mixture will be Ka NH 10 a 4 1 b 4 8 c 5 4 d 6 2

What is the maximum pH required to prevent the precipitation of ZnS in a solutio that is 0 01 M ZnCl and saturated with 0 10 M H S Given Ksp ZnS 10 K K of H S 10 2 A 0 C 2 B 1 D 4

2 Calculate the weight of NH4Cl that should be added to 100 mL of 1 M NH4OH to get pH 9 3 Consider no change in volume A plot the titration data to get the titration curve and locate the equivalence point

K for acetic acid is 5 x 10 then the degree of hydrolysis of 0 5 M Sodium acetate solution will have the following value 1 2 x 10 2 2 104 3 2 105 4 2 106

9 Propanoic acid CH CH COOH which we simplify as HPr is an organic acid whose salts used to retard mould growth in foods The balanced equation is shown below HPrag H O Pr aq H O g Which of the following is the correct expression for the acid dissociation constant K Pr H 0 A B K PrH O HPT H O C D K K PrH 0 HP HP HO PrH 0 odgsod

D Phosphorylation of glucose is non spontaneous a 300K AG is found to be 14 kJ mol 1 Th thermodynamic equilibrium constant will be 1 3 65 10 2 3 65 10 3 3 3 65 x 10 4 4 3 65 10 5

14 3 20 4 400 Ammonium carbamate dissociates as 2x NH COONH 2NH 4 s 20 In a closed vessel containing am 1 3 3 g ammonium carbamate in equilibrium ammonia is added such that the partial pressure of NH3 now equals to the original cototal pressure The ratio of total pressure now to the original pressure is 27 31 4 CO2 g 31 2 27 4 N M 5P 9 P PT 2p2 pa x p x

2 alitative analysis the metals of group I can be separated from other ions by precipitating them as chloride salts A solution initially contains Ag and Pb at a concentration of 0 10 M Aqueous HCl is added to this solution until the CI concentration is 0 10 M What will the concentrations of Ag and Pb2 be at equilibrium Ksp for AgCl 1 8 x 10 10 1 7 10 a Ag 1 8 107 M Pb 1 7 x 10 Ma 2 b Ag 1 8 10 M Pb 8 5 x 10 5 M c Ag 1 8 10 M Pb 1 7 10 M d Ag 1 8 10 1 M Pb 1 7 104 M Mains 2011 1 8 10 0 Ksp for PbCl2 9 20

A container is divided into 3 identical parts by fixed semipermeable membrane as shown below SPMI SPM II I 1 0 4 mole ii H 9 mole iii N 2 mole Permeable Permeable to H O to H N In compartment i 4 moles of O2 are taken In compartment ii 9 moles of H are taken In compartment iii 2 moles of N2 are taken Calculate the ratio of total pressure in the three compartments after a sufficient long time Assume temperature constant throughout If ratio is a b c simplest ratio then express your answer as a b c

3 If the concentration of the salt AB in the aqueous solution is 5 0 x 10 5 M K for the salt is 3 6 x 10 M Then which sentence describe the solution most correctly 1 The solution is supersaturated 2 The solution is unsaturated

8 Consider the following equilibria A s B s I III A s B g Which of the above will not be disturbed by increase in pressure A I and IV CIL III and IV II 2A l B l IV A g B g B I II and IV D IV only

For the reaction PC13 g Cl g PC1 g the value of Kc at 600K is 24 63 The value of Kp at this temperature will be 1 0 5 2 0 7 3 0 83 3 PC13 g Cl g PCI g 600K K 1 0 5 2 0 7 3 0 83 4 0 9 Kc24 63 4 0 9

pk of acetic acid is 4 74 which a implies that A pH of 1N acetic acid is 4 74 B C D at pH 4 74 the dissociation of acetic acid is maximum at pH 4 74 half of acetic acid molecules are dissociated in the solution at pH 4 74 the dissociation of acetic acid is minimum

H O 1 1 bar 373 K H O g 1 bar 373K the correct set of Thermodynamics parameters are 1 AG 0 AS ve 2 AG 0 AS ve 3 AG ve AS 0 4 AG ve AS ve A solution of a metal ion when treated with KI gives a red precipitate which dissolves in excess

NO and Br at initial partial pressures of 98 4 and 41 3 torr respectively were allowed to react at 300K At equilibrium the total pressure was 110 5 torr Calculate the value of the equilibrium constant and the standard free energy change at 300 K for the reaction 2NO g Br g 2 NOBr g 2NO g Br g 2NOBr g

Cas s 2CaO s 2SO2 g O g AH 0 ove equilibrium is established by taking sufficient amount of CaSO4 s in a closed container at 00 K Then which of the following may be correct option Assume that CaSO4 is present in the ntainer in each case on Moles of CaO s will increase with the increase in temperature Rate this quest If the volume of the container is doubled at equilibrium then partial pressure of SO g change at new equilibrium If the volume of the container is halved partial pressure of O g at new equilibrium remain same If two moles of the He gas is added at constant pressure then the moles of CaO s increase

3 Addition of trans 1 2 diol 4 Addition od Na HPO 50 Solid Ba NO is gradually dissolved in a 1 0x10 M Na CO solution At what concentration of Ba will a precipitate begin to form K for BaCO 5 1 10 3 8 1 10 M 1 5 1 10 M 2 8 1 10 M 4 4 1 10 M 51 In which process fused sodium hydroxide is electrolysed for extraction of sodium

1 With reference to the main group elements exclude P briefly state what is suggested about the origin of life on Earth Maximum word count 100 ii With reference to iron briefly outline what the data suggests about the origin and evolution of life on Earth Maximum word count 150 Log lelement human body Mg Ca K C 0 2 Si 2n Cu Fe 4 8 Log element in sea water Figure Comparison between the molar concentration 10 Co

A chemical reaction 2NH N 3H is taking place in the following apparatus The wall between NH and He is frictionless and mobile Initially only NH is present in the left chamber As NH dissociates at constant temperature the pressure in the chamber containing He becomes atm After this the pressure does not change further Find K for the given reaction Initially P 10 atm NH A 192 10L 64 9 C HeP 10 atm 10L 40 3 B 64 D None of these

The average concentration of SO2 in the atmosphere over a city on a certain day is 10 ppm wh the average temperature is 298 K Given that the solubility of SO2 in water at 298 K is 1 36 moles litre and the pKa of H2SO3 is 1 92 estimate the pH of rain on that day 2000