Equilibrium Questions and Answers

Two moles of N O4 is heated to form NO and 02 As soon as NO and O2 are formed they react to form N2O5 Two equilibria N O4 2NO O2 3 2NO O2 N O5 Are simultaneously established At equilibrium the degree of dissociation of N O4 was found to 50 Which of the following is correct at equilibrium 1 NO 0 2 2 N O NO 2 0 2 05 3 NO 0 N2O4 N O5 N O5 0 NO 2 1 4 2

Which of the following statements is are false for the pH of a 0 01 M Na3PO4 solution versus the pH of a 0 01 M in FeSO4 solution Select all that apply The activity coefficient for H is smaller in 0 01 M Na3PO4 than in 0 01 M FeSO4 The H activity in 0 01 M Na3PO4 is not equal to the HT activity in 0 01 M FeSO4 The H concentration in 0 01 M Na3PO4 is equal to the HT concentration in 0 01 M FeSO4 The activity coefficient for OH is larger in 0 01 M Na3PO4 than in 0 01 M FeSO4 The OH activity in 0 01 M Na3PO4 is not equal to the OH activity in 0 01 M FeSO4

For an elementary 2A 3B 3B reaction k k dissappearance of B is Question Type Single Correct Type 1 k A B k C 2C The rate of 2 3K A B 3k C 3 2k A 2 B 3 2k C

37 When a certain amount of ethylene was burnt 6226 kJ heat was evolved If heat of combustion of ethylene is 1411 kJ the volume of O2 at NTP that entered into the reaction is a 296 5 mL c 6226 x 22 4 litre b 296 5 litre d 22 4 litre

4 43 kJ mol Equivalent weight of Fe3O4 during the followin change is M molar mass of Fe3O4 3 Fe3O4 Fe O3 mol M 1 2 M 3 3 At low pressure Vand 3M 8 4 zla

B 10 points You are interested to determine the molar mass and acid ionization constant for a weak monoprotic acid You weigh out 1 98 g of this sample and titrate with 0 4890 M sodium hydroxide with an initial pH of 4 75 After adding 26 32 mL of the base the reaction reached completion From this data what is the molar mass and acid ionization constant of the unknown acid assume you use 20 0 mL of the acid for your titration

answer q31 12 31 Why is it necessary to use acetic acid and not sulphuric acid for acidification of sodium extract for testing sulphur by lead acetate test

What is the pH of a 0 95 M solution of HCO H which is also 0 25 M in NaCO H Note K 1 8 x 104 for HCO H Show work and give answer to correct number of significant figures What type of solution is this 1 point

9 3 log 0 0 5 11 5 Mustration 11 Calculate the degree of hydrolysis of a mixture of aniline and acetic acid each of them being 0 01 M of acetic acid 1 8 x 10 5 and K aniline 4 5 x 10 10 Also calculate pH of the mixture

3 4 The ionisation constant K for hydrazine N H is 1 0 x 10 6 What would be the age hydrolysis of 0 001 M N HC a salt containing acid ion conjugate to hydrazine base A025 M coluti K 2 0 10 5

Which of the following is the best definition of a chemical change A Something that can be observed or measured without changing the identity of the substance B A change that alters the identity or chemical composition of a substance at the atomic level C The ability of something to undergo a change or reaction

A buffer solution was obtained by adding 15 0g of CH3COOH and 20 5 of CH3COONa The buffer is diluted to Calculate the pH of the solution What will be the change in pH if 10 0 mL of 1 0 M HCl is added to it pk of acid 4 74 Given log 0 13 12 0 035

cca 0 6 mL of acetic acid CH COOH having density 1 06 g mL is dissolved in 1 litre of water The depression in freezing point observed for this strength of acid was 0 0205 C Calculate the van t Hoff factor and the dissociation constant of acid

2 g of benzoic acid CH COOH dissolved in 25 g of benzene shows a depression in freezing point equal to 1 62 K Molal depression constant for benzene is 4 9 K kg mol What is the percentage association of acid if it forms dimer in solution 25 d

2 10 points When you mix cadmium II ion and hydrogen sulfide does a precipitate of cadmium sulfide form You are given 0 10 M cadmium II ion and 0 10 M hydrogen sulfide and the solution yields a pH of 3 00 Ksp CdS 8 x 10 28 and Ka1 H2S 1 0 x 10 26

A solution contains 0 15M CI and 0 15M CO32 Ag is slowly added The Ks for AgCl is 1 6x10 10 and the Ksp for Ag CO3 is 8 2x10 12 Assuming no diluti of the solution which of the following statements is TRUE A AgCl precipitates first at a silver ion concentration of 1 1x10 M B AgCl precipitates first at a silver ion concentration of 3 5x105 M C Ag CO3 precipitates first at a silver ion concentration of 7 4x10 6 M D Ag CO3 precipitates first at a silver ion concentration of 5 4x10 M E No precipitate forms

An indicator is a weak acid and pH range of its colour is 3 0 to 4 4 The ionisation constant of indicator is log 2 0 3 Question Type Single Correct Type 1 2 x 10 5 M 2 2x10 4M 3 4 10 M 4 4 x 105 M

10 ii lonic Equilibrium aqueous solution of acetic acid is mixed with 500 ml of 0 2 M HCl at 25 C Ka acetic acid 2 105 Calculate the degree of dissociation of acetic acid in the resulting solution and pH of the solution If 6g of NaOH is added to the above solution determine the final pH SOLUTION 0 2 CH COOH Just after mixing 0 1M 2 0 2 HC Just after mixing 2 Note Equal volumes added t 0 conc CH3COOH CH3COO H 0 0 1 leq c ca 0 1M H From HCI CH3COO H K CH3COOH H Total H From CH COOH H From HCI and H Total pH 1 ca co 0 1 0 1 c ca c a will be small due to common ion effect K ax0 1 Ka 0 1 ca ca 0 1 c ca ca 2 10 4 Check 1 a 1 2 104 1 co 0 1 0 1x2x10 0 1 0 1 M ii 6 gm NaOH 6 40 1 0 15 gmeq 150 mmoles NaOH These will react with CH COOH as NaOH CH COOH CH COONa H O 50 100 50 Mmoles HC1 500x0 2 100 mmoles NaOH will first react with HCl and if there is a leftover then it will react with CH COOH Mmoles NaOH left 150 100 50 Formation of an acidic buffer Salt Acid pH pK log10 50 4 7 log10 50 VTotal 50 V Total 4 7

Consider the reaction Cl aq H S aq S s 2H aq 2Cl aq The rate equation for this reaction is rate k Cl H S Which of these mechanisms is are consistent with this rate equation 1 Cl H H Cr CI HS CI HS H Cr S 2 H SH HS Cl HS 2Cr H S 1 B only 3 Neither A nor B slow fast fast equilibrium slow 2 Both A and B 4 A only

A mixture of 2 3g formic acid and 4 5g oxalic acid is treated with conc H SO4 The evolved gaseous mixture is passed through KOH pellets Weight in g of the remaining product at STP will be NEET 2018 O examsnet com O 1 4 O 3 0 O2 8

A buffer solution of pH 9 80 is to be prepared from 1 M NH4Cl and 1 M NH3 solution pk of NH3 is 4 74 In 1 litre of the buffer solution volume of NH4Cl is log 0 28 0 54 Question Type Single Correct Type 1 200 ml 2 775 ml 32 500 ml 4 225 ml C

Pure gas A was taken in a closed container at an initial pressure of 5atm the pressure in the container changed due to the reactions AB 2C g 8 g CB D g If the total pressure due to the mixture of gases A B C and D was found to be 10atm at equilibrium in which pressure due to C was 3 atm then kp for the first equilibrium is

63 The first and second dissociation constants of an aci X H A are 1 0 x 10 6 and 5 0 x 10 10 respectively Th overall dissociation constant of the acid will be 1 5 0 x 10 5 2 5 0 x 1015 3 5 0 x 10 15 4 0 2 x 105 k K 6 2 50000 100000 x 10

FeCl3 solution fraction of solute in an aqueous solution which boils at 100 104 Kb for H O 0 52 K molality 3 6 10 XBX 1000 c 5 6 10 3 1 2 0 004 One mole of non volatile solute is dissolved in two mal d 0 996 14 of water Th 0 104 1 58 5

Question Number 158 Question Id 8135612078 Question Type MCQ Display Questi Number Yes Is Question Mandatory No Single Line Question Option No Option Orientation Vertical The equilibrium constant for the reaction the A2 g B2 g 2AB g is K The equilibrium constant for the reaction 2AB g B2 g 2AB2 g is K Find the equilibrium constant K for the reaction AB2 g A2 g B2 g in terms of K K A2 g B2 g 2AB g 2AB g B g 2AB2 0 AB2 g 42 g B2 g og Options 1 N 2K K 4K K K K 0 500 50 K and Soo K K K d

30 Equilibrium PCI5 PCl3 Cl constant of the reaction 1 Increases with increase in temperature 2 Decreases with increase in temperature 3 May increase or decrease with increase in temperature 4 Doesn t change with increase in temperature

73 Solubility of Mg OH in water is 1 10 4 The pH 7 at which it starts to precipitate in an aqueous solution having 0 04 M Mg2 will be 1 7 2 8 3 9 4 5 Chemical method for removal of temporary 74 7

Which of the following salts shows the lowest solubility g L in water Ksp values Ag2S 1 6 x 10 49 Bi S3 1 0 x 10 72 Hgs 1 6 x 10 54 Mg OH 2 8 9 x 10 12 MnS 2 3 10 13 Molar masses in g mol Ag2S 247 8 Bi2S3 514 16 HgS 232 7 Mg OH 2 58 3 MnS 87 0 O A82S O Bi S3 O MnS O Mg OH 2 OHgS

Question Number 148 Question Id 8135612228 Question Type MCQ Display Question Number Yes Is Question Mandatory No Single Line Question Option No Option Orientation Vertical For the equilibrin 50 g O2 g 50 g set up in a cylinder fitted with a piston an inert gas is added and the piston is moved outwards to keep the total gaseous pressure constant Which of the following situations may occur Aus de 50 0 Jaider God SO g 02 g 503 g Doyberdende aderat de sudes en ba o 30 d v sobo So are D 85 Daya Options 1 Ja 2 3 Addition of inert gas does not affect equilibrium x Less S03 g sexy save so is produced SO3 g Jawa More SO3 g is produced SO3 g Jaws Dan The system attains a new equilibrium position Od Jow

how we got to know that concentration is not 1M in the la t step s Esc to exit full screen Mn ne M C IM Q M M t ERHE ERHE 0 0591 log Qc 1 0591log 00002746141 aesl in M h ERHE ERHE 0 0591 log ny

43 4 moles of N O4 g at 300 K is kept in a closed container under 1 atmosphere It is heated upto 600 K when 20 of mass of N O4 decomposes to NO2 g The resultant pressure is a 1 2 atm c 2 atm b 2 4 atm d 1 atm 1 1 BHU in

In Lindemann theory of unimolecular reactions it is shown that the apparent rate k C constant for such a reaction is kapp where C is the concentration of th ac reactant k and a are constants The value of C for which kapp has 90 of its limiting value at C tending to infinitely large is 1 105 A 10 5 B 10 7 c 10 9 1

Two closed bulbs of equal volume V containing an ideal gas initially at pressure p and temperature T are connected through a narrow tube of neglifible volume as shown in the figure below The temperature of one of the bulbs is then raised to T The final pressure p is 2 JEE MAIN 2016 1 Pi COCO T T T T T P V T 2 2p P V T T T T PBV 2P T T T Pf V 4 2p 2p T T T T 5 that of gas B at same

If K is the equilibrium constant for the reaction 2NO g O g 2NO g and K2 is the equilibrium constant for the reaction 2NO g constant for the reaction 2NO g O g N 04 g is given by N 04 9 then K3 the equilibrium Question Type Single Correct Type 1 K3 K K 2 K3 K K X 3 K3 K K K

If for the equilibrium PC15 g PCl3 g Cl g 1 molar PC15 is present initially and at equilibrium 0 6 M Cl is formed than the value of Kc for the given reaction is 10 11 10 9 10 10

Consider the reaction A B at 1000 K At time t the temperature of the system wa increased to 2000 K and the system was allowed to reach equilibrium Throughout this experimen the partial pressure of A was maintained at 1 bar Given below is the plot of the partial pressure o B with time What is the ratio of the standard Gibbs energy of the reaction at 1000 K to that a 2000 K ms 0 25 l Keq K1000 B A Now 10 1 AG 10 and K2000 1000 Partial Pressure of B bar 100 1 RT nk 1000 115 100 50 10 100 1000x n10 time

14 0 d 13 0 The value of the ion product constant for water K at 60 C is 9 6 10 4 M What is th H3O of a neutral aqueous solution at 60 C and an aqueous solution with a are respectively a 3 1x 10 8 acidic c 3 1 x 10 8 basic p kia b 3 1x 10 7 neutral d 3 1 x 10 7 basic a pH 7 0 at 60

2 For the following reaction A strip of chromium metal is placed in an acidic solution of aqueous aluminum nitrate T 7 b Write out the oxidation and reduction half reactions from your results in a and the net reaction 4

Equilibrium for which Kp Kc is CaCO3 s CaO s CO g PC15 g PC 3 s Cl g 2 SO3 g 2 SO g O g H g 1 g 2 HI g

The solubility of BaSO in water is 2 42 10 gL at 298 K The value of its solubility product Ksp will be Given molar mass of BaSO 233 g mol 1 1 08 10 10 mol L 2 2 1 08 10 12 mol L 2 3 1 08 10 8 mol L 2 4 1 08 x 10 14 mol L 2 NEET 2018

pH of the aqueous solution of salt of weak acid with weak base is 7 PK PK 7 PK PK 7 7 12 PKa PK 7 pKb pka

03 x ml of HCI is required for titration of a mixture of Na CO3 NaHCO3 with phenolphthalein as indicator and y ml of HCI with Methy orange as indicator in same titration Volume of HCI required for complete reaction of Na CO3 is 1 2y 2 2x 3 4 x y 2 X Y 2

Example of homogeneous equilibrium is C s CO g 2 CO g H O l H O g Ca OH s aq Ca aq 2OH aq N 04 g 2 NO g nr

an evacuated vessel of capacity 112 L 4 moles of Ar g and 5 moles of PCs 8 were introduced and the temperature is maintained at 273 r At equilibrium the otal pressure of the mixture was found to be 4 8 atm A B C D The degree of dissociation of Cl g is 0 6 PCI g into PC1 g and Kp for the reaction PCls g PC13 g Cl g is 2 7 atm At equilibrium the total moles of gases are 12 On removing Ar g from the equilibrium mixture at constant pressure and temperature the extent of dissociation of PCIs will increase

56 Mg OH is precipitated when NaOH is added to a solution of Mg2 If the final concentration of Mg2 is 10 10 M the concentration of OH M in the solution is Solubility product for Mg OH 5 6 10 2 2 a 0 056 b 0 12 c 0 24 d 0 025 7 A constant current 0 5 amp is passed for 1 hour A NO mo

M solution of H SO4 is electrolysed Select correct statement in respect of products obtained at anode and cathode respectively Given 250 S 02 2e E 2 01 V H O 0 2H aq 1 2O g 2e E 1 23 V a concentration of H SO4 remain constant H 0 b concentration of H SO4 increases O H e concentration of H SO4 decreases O H d concentration of H SO remains constant 0 H

is inversely proportional to the square root of its concentration A buffer solution contains 0 3 mol dm 3 NH4OH is 1 8 x105 Calculate pOH Ans 4 8686 the solution

If Kc for the equilibrium N 3 H 2 NH3 is x then Kc for 1 3 the equilibrium NH3 N2 H i is NIX 2 2 x III x

A saturated solution in AgA K 3 10 4 and AgB K 1 10 has conductivity of 375 10 Scm Limiting molar conductivity of Ag and A are 60 Scm mol and H 80 Scm mol respectively If the limiting molar conductivity of B is Y in Scm mol Find out the value of Y 54

K for the reaction N 3H 2NH3 is 1 645x10 4 atm 2 at 400 C What will be the K at 500 C Heat of reaction in this temperature range is 25 14 kcal 1 Greater than 1 645x10 4 atm 2 Smaller than 1 645x10 4 atm 3 Equal to 1 645x10 4 atm 4 Greater than or equal to 1 645x10 4 atm