Equilibrium Questions and Answers

NH HS s NH g H S g Above reaction attains equilibrium at 20 C and 6 atm pressure Choose correct statements regarding the reaction The partial pressure of NH3 is higher than that of H S The equilibrium constant Kp 9 atm Kp Ko Removal of NH3 increases the yield of H S

20 Match List I Equations with List II Type of process and select the correct option List l Equations a K Q b AGO RT In Q c K Q d T 101 AH AS m List II Type of process AIPMT Mains 2010 1 a i b ii c iii d iv 2 a iii b iv c ii d i CORY i Non spontaneous ii Equilibrium iii Spontaneous and endothermic iv Spontaneous

1 Following simultaneous equilibrium takes place in 1 L container 2P g P g P g Q g R s At equilibrium degree of association of P is 0 5 and degree of decomposition of P2 is also 0 5 The vapour density of P and equilibrium mixture are D and d respectively The value of 12 MQ d M and M are molar mass of O and Pl 1 is Given

At 200 C PC1 dissociates as follows PCI g Cl g PC1 g 21 x It was found that the vapours of equilibriu mixture are 62 times as heavy as hydrogen Th degree of dissociation of PC1 at 200 C nearly 1 10 2 42 62 1 6 62

Sulphide ion reacts with solid sulphur S aq S s S S S2 2 aq 2S s S aq K 130 The equilibrium constant for the formation of S 2 aq from S 2 aq and sulphur is 1 10 2 13 3 130 4 1300 aq aq K 10

An acidic buffer is obtained on mixing 100 ml of 0 1 M CH3COOH and 100 ml of 0 1 M NaOH 100 ml of 0 2 M H3PO4 and 100 ml of 0 1 M NaOH 200 ml of 0 1 M HCI and 200 ml of 0 1 M Na3PO4 100 ml of 0 1 M HCI and 100 ml of 0 1 M NaOH

4 The dissociation constants for acetic acid and pyridine are 1 8 x 10 5 and 1 5 x 10 9 respectively Calculate the degree of hydrolysis of pyridinium acetate in its 0 1 M solution What will be the effect on degree of hydrolysis when 1 litre of the above solution is mixed with 1 litre of water

Consider an irreversible reaction A B C with a rate law R c If B o were 1 mol L t s A x 10 mol L B mol L 0 2 1 10 1 1 20 1 2 1 What would be the overall order of the reaction Unknown What would be the order of the reaction with respect to A 1 What would be the order of the reaction with respect to B Unknown k A n B m 30 1 4 1

Gases A2 B are present in two containers I II respectively at 300K separated by a narrow tube of negligible volume closed by a valve On opening the valve reaction given below attains equilibr T 2 mol A g 3 L 300 K A g B g 2AB g Kp 4 Equilibrium molar concentration of AB g is 4 mol B g 300 K

D 5 moles of SO 2 and 5 moles of O2 are allowed to react At equilibrium it was found that 60 of SO2 is used up If the pressure of the equilibrium mixture is one atmosphere the partial pressure of O is a 0 52 atm b 0 21 atm d 0 82 atm c 0 41 atm

1 For the process 3 2 AB at 298 K AG is 163 kJ mol The composition of the reaction mixture is B 1 and A 10000 Predict the direction of the reaction and the relation between reaction quotient Q and the equilibrium constant K

3 In a system A s 2B g 3C g if the concentration of C at equilibrium is increased by factor of 2 it will cause the equilibrium concentration of B to change to a two times the original value b one half of its original value 1 c 2 2 times to the original value d times the original value 2 2

The molar heats of fusion and vaporization of benzene are 10 9 kJ mol and 31 0 kJ mol respectively If at 1 atm benzene melts at 10 9 C and boils at 62 C Which of relation for ASfus and ASvap is true O ASfus ASvap O ASfus ASvap O ASfus ASvap O All are true

5 Which of the following is the correct value of pH for solution obtained by adding 4 g of NaOH to 1 L of solution of a buffer containing 60 g of acetic acid and 1 mol of sodium acetate K of acetic acid 0 000018 Choose the correct choice choices A log 0 18 10 4 log C log 0 018 x 10 7 log No 25 nc An B log 0 018 x 10 5 log 11 D 4 83

01 9 An air bubble has a radius of 0 50 cm at the bottom of the water tank where the temperature is 280 K and the pressure is 280 kPa When the bubble rises to the surface the temperature changes to 300 K and pressure is 100 kPa Calculate the radius of the bubble at the surface

Given are E values for some half reactions 12 2e 21 E 0 54 V MnO 8H 5e Mn 4H O E 1 52 V Fee Fe2 E 0 77 V E 0 1 V Sn 2e Sn The strongest reducant and oxidant respectively are Sn MnO4 MnO4 Sn 12 Fe

The equilibrium constant gives information about which direction of a reaction is favored If the K for the reaction shown below is 1 1 x 107 which compound s is favored 2 H2 g S2 2 H S H S O H and S H

At equilibrium the reaction H Cl 2 HCI has a Ke of 8 0 and contains HCI 2 0 M and Cl 1 0 M What is the equilibrium concentration of the hydrogen gas 2 0 M O 0 5 M 0 25 M 4 0 M

2 3 2 moles N O4 were introduced in a flask of 10 litre capacity at 350 K At equilibrium 50 of N O4 was found to be dissociated into NO Find out equilibrium constant for the dissociation of N O4 under the given conditions

Example 7 6 Calculate the acetic acid if its K 1 8 x 105 What would be the degree of ionization if the solution also contains 0 01 M sodium acetate Solution CH COOH aq CH COO aq H aq The degree of ionization of this weak acid can be calculated by the approximate relation V C Ka 1 8 x 10 5 0 02 Now let us calculate the degree of ionization when the solution also contains 0 01 M sodium acetate Sodium acetate being a strong electrolyte would be completely ionized in solution Let x mol L 1 of acetic acid be ionized CH COOH aq CH COO aq H aq 0 02 x M x M x M CH3COONa aq CH3COO aq Na aq 0 01 M 0 01 M 18 x 107 H x mol L CH COO x 0 01 mol L 0 01 mol L 1 x is very small as compared to 0 01 CH COOH 0 02 x mol L 0 02 mol L 1 H CH COO CH COOH K 5 x x 0 01 0 02 x 3 6 x 10 5 H 3 6 x 10 5 M Degree of ionization 0 03 3 x 10 r 3 6 10 5 1 8 x 104 0 02 0 02 Thus it may noted that the degree of ionization of acetic acid has decreased from 3 x 10 2 to 18 x 10 due to the presence of sodium acetate Sodium acetate suppresses the degree of ionization of

1 A buffer is made from the aminium salt of an amine e g R NH3 and the neutral amine e g R NH If the aminium form has a pK of 10 6 and the pH is measured to be 11 1 then what fraction of the compound will be in unprotonated amine amino form Enter your answer as a percent to the nearest ones

10 g sample of gas liquor NH salt is boiled with NaOH and the resulting NH3 is passed into 60 ml of 0 90 N H SO4 Excess H SO4 required 10cm of 0 40 N NaOH What is the of NH3 in gas liquor A 8 5 C 9 5 B 7 5 D 10 5

One mole of acetic acid and one mole of methyl alcohol were mixed at 298 K At equilibrium 0 333 mole of acetic acid was found to be unreacted Calculate the equilibrium constant for the reaction

A chemical reaction is carried out by starting with one mole each of H and I in closed vessel at 717 K No more change in concentration was observed after 1 56 mole of HI is formed If we start the reaction with 2 mole of HI under similar conditions how many moles of H and I will be formed

Calculate the equilibrium concentration of Mg2 and F 1 1 0L of 6 0 10 M Mg NO3 2 is added to 2 0L of 3 0 10 M NaF Calculate the equilibrium concentration of Mg2 and F Kap of MgF2 4 0x10 5 pts

Fe s CO g For a reaction FeO s CO g the value of K at 1373 K is 0 505 If the reaction mixture has 1 mole each of Fe and FeO 1 5 atm CO and 0 6 atm CO in which direction will the reaction go

2NO g at Consider the reaction N O g 373 K Suppose at a particular moment concentrations of N O4 and NO are 1 mol L each In which direction the reaction will proceed to establish equilibrium K for the reaction is 0 36 2

For the reaction 2A B 3C d B dt between K K and K3 is 1 K K K 2 2K K 3K3 K A d C dt AV 21 dt A K A the correct relation

The equilibrium constant K for decomposition of gaseous H O H O g H g O2 g is related to degree of 2 dissociation a at a total pressure P given by 1 Kp 2 Kp 3 Kp 3 1 2 a p 1 a 2 a 2 33 2 a p 1 a 2 a the a 2p 2 1 a 2 a 3 2 1 2

2 A reaction mixture containing 0 50 atm N 3 0 atm H and 0 50 atm of NH3 is heated to 725 K If the value of K at 725 K is 4 28 x 10 5 atm 2 in which direction the following reaction will go N g 3H g 2NH g

Find the pH during the titration of 25 00mL of 0 150 weak acid with 0 250 M strong base solution Ka 1 08 10 5 Kb 9 25 10 10 FIND a Buffer solution b At equivalence point c At half equivalence point d 2mL to the right of Half equivalence point e 2mL to the equivalence point

For the reaction 12 g Cl g 2ICI g ArxnG 10 91 kJ mol For an initial reaction mixture which contains P12 0 114 bar PC12 0 102 bar and PICI 0 355 bar what will happen in this system System is not at equilibrium and will shift towards reactants System is not at equilibrium and will shift towards products More information is required to answer this question System is at equilibrium and thus no change will occur

non ionized forms of the drug novocaine in the stomach pH 1 98 and the intestine pH 8 98 if its pk 8 98 Where will the drug be absorbed in the stomach and or intestines

If 14 kg of N reacts with 15 Kg H 50 yield to form NH3 then which of the following is are correct 1 17 Kg of NH3 will be formed 2 7 Kg N will remain left 3 12 Kg of H will remain left 4 All of these

For the given reaction 2A s B g C g 2D s E s the extent of reaction of B was found to be 20 at 300 K and 24 at 500 K The rate of backward reaction a increases with increase in pressure and temperature b increases with increase in pressure and decrease in temperature c depends on temperature only and decreases with increases in temperature d depends on temperature only and increases with increase in temperature

For the reaction A B s 2Cg Kp 16 atm at 1000 K In a vessel of 20 5 litr moles of B are taken at 1000 K and then 2 moles of C are added Assuming volume occup by the solid to be negligible predict 1 Nothing can be predicted in the absence of sufficient data 2 Nothing would happen 3 An equilibrium will be set up with the formation of 0 5 moles of A 4 B and C would react completely to form A

Calculate the pH of a buffer solution that is 0 245 molal in CH3COOH Ka 1 75x10 5 and 0 375 molal in CH3COONa using the Davies equation to calculate y at 298 15 K calculated What pH value would you have if you had assumed that y 1

Cu 2e Cu E 0 34 V Ag e Ag E 0 80 V For what concentration of Ag ions will the emf of the cell be zero at 25 C concentration of Cu is 0 1 M log 3 919 0 593 A 8x10 M B 7 10 M C 6 10 M D 5x11

At 650 K the reaction MgCO3 s MgO s CO2 g has an equilibrium constant Kp 0 026 A 10 0 L container at 650 K has 1 0 gram MgO s and a CO2 g pressure of 0 0260 atm The container is then compressed to 100 It 15 1611

ogen gas and lodine gas react via the ing equ Kc 79 at 650 K If 0 031 mol HI is placed in an empty 1 0 L flask at 650 K what are the equilibrium concentrations of HI I2 and H M M M HI ba 6 IH Z 6 1 6 H

2NH3 g 61 N g 3H g For the reaction initially the mole ratio was 1 3 of N H At equilibrium 50 of each has reacted If the equilibrium pressure is P the partial pressure of NH3 at equilibrium is P 3 a b P 4 c P 6 d P 8

Given the following equilibrium reaction identify the effect each change will have as the reaction shifts to reestablish equilibrium CO g C s O g AH 256 kJ Decide if each change would cause the reaction to shift to favor reactants products or cause no change Change Increase in temperature Increase in concentration of C s Decrease in O g Add a catalyst Increase in concentration reactants Effect on Equilibrium

Solid NH HS dissociates into NH3 and H S at a certain temperature the equilibrium pressure is P atm If now NH3 is pumped into the system so that its partial pressure becomes P atm then what will be the partial pressure in atm of H S b 0 25 P d 0 67 P a 0 5 P c 0 33 P

67 At 27 C and 1 atm pressure N O4 is 20 dissociation into NO What is the density of of N O4 and NO2 at 27 C and 1 atm equilibrium mixture a 3 11 g litre b 2 11 g litre c 4 5 g litre 600 ding th ation COCI Lo d None of these COLCC When heater

10 13 Describe how you would prepare exactly 100 mL of 0 100 M picolinate buffer pH 5 50 Possible starting materials are pure picolinic acid pyridine 2 carboxylic acid FM 123 11 1 0 M HCI and 1 0 M NaOH Approximately how many milliliters of the HCI or NaOH will be required

the equilibrium constant for the reaction 2SO g O g 2SO g has a value of 278 at a particular temperature What is the value of the equilibirum constant for the following reaction at the same temperature SO g SO g 1 1 8 10 3 10 O g AIPMT Mains 2012 276 2 3 6 10 3 4 1 3 x 10 5

Solid calcium fluoride and solid barium fluoride are in equilibrium with a solution containing 9 76 103 M barium acetate Calculate the concentration of calcium ion present in this solution calcium M

The Haber Bosch process involves the combination of nitrogen and hydrogen at high temperatures in the presence of a catalyst to produce ammonia It is currently the main industrial source of ammonia N g 3H g 2NH3 g Assuming that a reaction vessel originally contains 0 350 moles of N and 0 550 moles of H answer each of the following questions a How many moles of NH3 could be produced from these quantities of N and H NH3 0 3667 b After the reaction is complete how many moles of N would remain N 0 1833 c After the reaction is complete how many moles of H would remain H 0 mol mol moles

Consider the following physical transformation X s X aq If one were to write an equilibrium constant K for the process Assi K X aq X s K X aq K

Example 7 8 Phosphorus pentachloride decomposes according to the equation PCI g PCl3 g Cl g 1 00 mol of PCl is placed in a closed container of 5 0 L capacity and heated to 523 K What will be the composition of the mixture when equilibrium is attained at 523 K The equilibrium constant K for the reaction at 523 K is 1 80