Equilibrium Questions and Answers

27 The reaction of hydrogen and iodine monochloride is given as H2 g 21Cl g 2HCl g 2 g This reaction is of first order with respect to H2 g and ICI following mechanisms were proposed Mechanism A H2 g 21Cl g 2HCl g 2 g Mechanism B H2 g ICI g HCl g HI g slow HI g ICI g HCl g 12 g i fast COLS Which of the above mechanism s can be consistent with the given information about the AIPMT Prelims 2007 reaction 1 A only 2 B only 3 Both 1 and 2

electric 4 5g of aluminium at mass 27 amu is deposited at cathode from Al solution by a certain quantity of charge The volume of hydrogen produced at STP from H ions in solution by the same quantity of electric charge will be 1 44 8L 2 11 2L 3 22 4L 4 5 6L

A 28 mL of a 0 45 M HF solution is titrated to the equivalence point with a 0 45 M NaOH solution What is the pH at the equivalence point The Ka for HF is Ka 6 6 x 10 4 Please express your answer to the 3rd decimal place

Consider the reaction Cl aq H S aq S s 2 H aq 2 Cl aq The rate equation for this reaction is rate k Cl H S Which of these mechanisms is are consistent with this rate equation A Cl H S H CI CI HS slow CI HS H CI S fast B H S Cl HS H HS fast equilibrium 2 CI H S slow O A only OB only O Both A B ONeither A nor B

Addition of water to which of the following equilibria causes it to shift in the backward direction a CH NH aq H O CH NH aq OH aq b AgCl s Agt aq Cl aq c HCN aq H O 0 H O aq CN aq d Cr dien aq 3H O 1 3Cl aq Cr H O Cl3 aq 2 dien aq ALIV 21

47 AG of reversible reaction at its equilibrium is 1 Positive 3 Always zero 2 Negative 4 May be 1 or Pyt Itd Regd Office Aakash Tower 8 Pusa

a Which of the following statements about pH and H ion concentration is incorrect 2000 Addition of one drop of concentrated HCl in NH OH solution decreases pH of the solution A solution of the mixture of one equivalent of each of CH COOH and NaOH has a pH of 7 c pH of pure neutral water is not zero b d A cold and concentrated H SO4 has lower H ion concentration than a dilute solution of H SO

Dilution process of different aqueous solutions with water are given in List I The effects of dilution of the solutions on H are given in List II Note Degree of dissociation a of weak acid and weak base is 1 degree of hydrolysis of salt 1 H represents the concentration of H ions Column I 10 mL of 0 1 M NaOH 20 mL P A of 0 1 M acetic acid diluted to 60 mL the value of 20 mL of 0 1 M NaOH 20 mL change to half of B of 0 1 M acetic acid diluted to 80 mL its initial value dilution 20 mL of 0 1 M HCl 20 mL c Of 0 1 M ammonia solution diluted To 80 mL 10 mL saturated solution of Ni OH 2 in equilibrium with excess solid Ni OH 2 is diluted to 20 mL solid Ni OH 2 is still present after Dilution Column II the value of H P does not change on dilution S P the value of H changes to two R times of its initial Value on dilution S the value of H 1 to times of 2 its initial value on dilution The value of H Changes to 2

The heat of neutralisation of four acids P Q R S are 13 7 9 4 11 2 and 12 4 kcal respectively they are neutralised by a common base The acidic character obeys the order 1 P Q R S 2 P S R Q 3 S

At 25 C the dissociation constant of a base BO is 1 0 10 12 The concentration of hydroxyl ions in 0 01M aqueous solution of the base would be AIPMT Prelims 2005 1 2 0 10 mol L 1 2 1 0 10 5 mol L 1 1 0 x 10 6 mol L 4 1 0 10 7 mol L

The values of Kp and Kp for the reactions X Y Z a 2008 and A2B b are in the ratio of 9 1 If degree of dissociation of X and A be equal then total pressure at equilibrium for a and b are in the ratio a 3 1 b 1 9 c 36 1 d 1 1

O 2e i in exp io nF RT R kb n exp cnF RT n Use equation above to plot a tafel cathodic curve for n 0 15 volts calculate for the current value for 0 1 0 25 0 45 and 0 6 Then plot log i vs overpotential

Consider the following reversible reaction A g B g AB g The activation energy of the backward reaction exceeds that of the forward reaction by 2RT in J mol If the pre exponential factor of the forward reaction is 4 times that of the reverse reaction the absolute value of AG in J mol for the reaction at 300 K is Given n 2 0 7 RT 2500 J mol at 300 K and G is the Gibbs energy 8500

P For a given exothermic reaction K and Kare the equilibrium constants at temperatures T and T2 respectively Assuming that heat of reaction is constant in temperature range between T and T2 it is readily observed that 2014 a K Kp T b K Kp P 1 IN IZ

The dissociation equilibrium of a gas AB can be represented as 2008 2 AB g 2AB g B g The degree of dissociation is x and is small compared to 1 The expression relating the degree of dissociation x with equilibrium constant K and total pressure P is P b 2K P 3 d K P a 2K P c 2K P 1 2

MY and NY two nearly insoluble salts have the same Ksp values of 6 2 x 10 13 at room temperature Which statement would be true in regard to MY and NY NEET 2016 1 The addition of the salt of KY to solution of MY and NY will have no effect on their solubilities 2 The molar solubilities of MY and NY in water are identical 3 The molar solubility of MY in water is less than that of NY 4 The salts MY and NY are more soluble in

70 The equilibrium constant of the reaction Zn Hg HgO s ZrO s Hg 1 having E 1 55 volt at 298 Kis 1 2 8 x 1052 3 3 5 x 1070 2 2 8 x 1040 4 3 5 1035

Which of the following is are correct for the reaction with equilibrium constant K A g B g c g D g AH 20 J 1 2 3 rrect Answer 1 2 3 kt Keq will increase on increasing temperature kt will increase on increasing temperture kb will increase on increasing temperature kb will decrease on increasing temperature

The reaction 24 g B g 3C g D g is begun with the concentrations of A and B both at an initial value of 1 00 M When equilibrium is reached the concentration of D is measured and found to be 0 25 M The value for the equilibrium constant for this reaction is given by the expression 2010 a 0 75 0 25 0 75 0 25 b 0 75 3 0 25 1 00 1 00 c 0 75 0 25 0 50 0 75 3 10 051 050 025

Correct statement s a At midway in the transition of an acidic indicator pH pk In b Methyl orange 3 1 to 4 4 is a suitable indicator for titration of weak acid and strong ba c Bromothymol blue 6 0 to 7 6 is a good indicator for titration of HCl and NaOH d Thymol blue 1 2 to 2 8 is a very good indicator for titration of 100 mL of 0 1 MNF pK 4 74 and 0 1 M HCl b ach titrated

5 d What is the percent dissociation of N O4 At some temperature and under a pressure of 4 atm PCl is 10 dissociated Calculate pressure at which PCls will be 20 dissociated temperature remaining same PCls dissociates according to the reaction Pl POLY

18 The pH of pure water at 25 C is 7 If heated to boil then 1 pH will decrease and water will become acidic 2 pH will increase and water will become basic 3 pH will decrease but water will remain neutral 4 pH will remain 7 2015 16

57 The standard e m f of a galvanic cell involving cell reaction with n 2 is found to be 0 295 V at 25 C The equilibrium constant of the reaction would be Given F 96500 C mol R 8 314 J K 1 mol 1 1 2 0 x 1011 2 4 0 1012 fp

A beaker with 155 mL of an acetic acid buffer with a pH of 5 000 is sitting on a benchtop The total molarity of acid and conjugate base in this buffe 0 100 M A student adds 4 10 mL of a 0 310 MHCl solution to the beaker How much will the pH change The pK of acetic acid is 4 740 Express your answer numerically to two decimal places Use a minus sign if the pH has decreased

500 mL of 0 4 M AgNO3 is mixed with 500 mL of 2 M NH3 solution then the conc of Ag NH3 of solution is represented as 3 3 10 then the value of x is Given Ag NH3 10 K Ag NH3 10

Application of Principles 2 Co solutions are also acidic because of an equilibrium like the one in the previous ques Co H O 2 aq H2O Co H2O s OH aq H O aq but with K 5 0 x 10 10 Calculate the pH of 0 10 M Co NO3 2 aq Number

Sodium sulphate is soluble in water whereas barium sulphate is sparingly soluble because i the hydration energy of Na SO4 is less than its lattice energy ii the hydration energy of Na SO4 is more than its lattice energy iii the lattice energy of BaSO4 is more than its hydration energy iv the lattice energy has no role to play in solubility 1 i ii 2 ii iii 3 iii iv 4 ii iv

Construct the expression for Kc for the following reaction FeO s H g Fe s H O g 1 Drag the tiles into the numerator or denominator to form the expression Kc

The solubility of a salt of weak acid AB at pH 3 is Yx 10 mol L 1 The value of Y is Given that the value of solubility product of AB Ksp 2 10 10 and the value of ionization constant of HB K 1 10 8 4

35 The hydride ion H is stronger base than its hydroxide ion OH Which of the following reaction will occur sodium hydride is dissolved in water 1 Haq H O HgO 3 H H O H O 2 H aq H O OH H 4 H H O No reaction

Note log2 0 3 All data are at 25 C Column I A 1 MXOH aq B PK XOH 6 0 1M C H NH aq PK C H NH 7 C At equivalence point when 20 ml of 0 5M BOH is titrated with 2M HC1 K BOH 1 4 10 M D 20ml 0 125M C H NHCl 5ml 5 10 M HCI K C H N 5 10 0M Column II P H OH Q pH 2 4 R POH 3 S pH 10

31 For the decomposition reaction NH COONH4 s 2NH3 g CO g the Kp 2 9 x 105 atm The total pressure of gases at equilibrium when 1 mol c NH COONH4 s was taken initially coul be 1 0 0194 atm 3 0 0582 atm 2 0 0388 atm 4 0 0766 atm

Match the properly given in column I with the compound given in column I Column I a Soluble in concentrated ammonia solution b Soluble in excess KCN solution c Soluble in excess hypo solution D Soluble in conc HCI Column II P Ag S Q Cu OH R AgBr S AgCl

increases on dilution because of 1 Increase in number of ions per unit volume 2 Increase in molecular attraction 3 Increase in degree of association 4 Increase in degree of ionisation of th substance

The enthalpy of hydrogenation of cyclohexene is 119 5 kJ mol If resonance energy of benzene is 150 4 kJ mol its enthalpy of hydrogenation would be a 208 1 kJ mol 1 c 358 5 kJ mol 1 2006 b 269 9 kJ mol 1 d 508 9 kJ mol 1

d 4 92 A mixed solution of potassium hydroxide and sodium carbonate required 15 mL of an N 20 HCl solution when titrated with phenolphthalein as an indicator But the same amount of the solution when titrated with methyl orange as indicator required 25 mL of the same acid The amount of KOH 93

The correct formula to calculate the hydroxyl 100 concentration of an aqueous solution of NH NO is 1 3 CxK V Kb CxK 1 K W W 2 4 V KwxKb W C K XK a C W

6 What is the OH in the final solution prepared by mixing 20 0 mL of 0 050 M HCI with 30 0 mL of 0 10 M Ba OH 2 AIPMT Prelims 2009 1 0 40 M 3 0 12 M 2 0 0050 M 4 0 10 M

Enter your answer in the provided box In a titration of HNO3 you add a few drops of phenolphthalein indicator to 50 00 You quickly add 20 00 mL of 0 167 M NaOH but overshoot the end point and the pink Instead of starting over you add 30 00 mL of the acid and the solution turns takes 7 13 mL of the NaOH to reach the end point What is the concentration of th

The solubility product of AgI at 25 C is 1 0 10 16 mol L2 The solubility of AgI in 104 N solution of KI at 25 C is approximately 1 1 0 10 16 2 1 0 10 12 3 1 0 10 10 4 1 0 10 8

A 2 0 L flask initially containing one mole of each CO and H O was sealed and heated to 700 K where the following equilibrium was established CO g H O CO 8 H 8 Kc 9 Now the flask was connected to another flask containing some pure CO g at same temperature and pressure by means of a narrow tube of negligible volume When the equilibrium was restored moles of CO was found to be double of its mole at first equilibrium Determine volume of CO g flask in litres

ugh pressure 5 The following are some statements regarding dissociation of lime stone according to the equation CaCO3 s CaO s CO2 g AH 110 kJ The reaction is carried in a closed vessel A The pressure of CO increases when temperature is increased B The pressure of CO increases when temperature is decreased C The pressure of CO increases when amount of CaCO is decreased The incorrect statements are 1 A and B 2 B and C 3 A and C 4 All A B C

The thermal dissociation equilibrium of CaC CaCO3 s CaO s CO g For this equilibrium the correct statement s is are A AH is dependent on T B K is independent of the initial amount of CaCO3 C K is dependent on the pressure of CO2 at a given T D AH is independent of the catalyst if any mperature

respectively then x y is equal to given K HA 106 K BOH 106 a xMnO yPbO zHNO3 HMnO Pb NO3 H O then minimum integer value of z y x is A complex of platinum molecular weight 600 forms two ions in solution contains 65 Pt 23 6 CL 9 3 N and 2 H Addition of silver nitrate to

What is the concentration of the undissociated acidic in a solution of amm with a pH of 7 800 The molar concentra of dissociated acid ion is 0 02000 The of ammonia is 9 250 0 01741 0 001741 8 704 08704

Calculate the molar solubility of CdS in 0 10 M NH3 Enter your answer as scientific notation with the correct number of sig figs Use the e format 2 Ksp for CdS 8 0 10 27 and Kf for Cd NH3 4 1 0 107

19 If the gas mixture for the following reaction is 2 x 102 What will be the 2NO2 N O g 2NO g is compressed then a products are favoured 5 com b reactants are favoured b mean s Volume I Pressure 7h00 8 Zn Expression for the parti above reaction would be c no change d products become equal to reactants 20 For a gaseous reaction pD Alexte reply which of the following relationship is true c K 21 For the reaction AR a K P ZnO CO ZnCO3 c K P ZnO P CO

3 The equilibrium P s 6C1 g 4PCl3 g is attained by mixing equal moles of P and Cl in a evacuated vessel Then at equilibrium 6 P Cl d PC1 P a Cl PC1 c Cl P CET 20

SolveLancer Test In an experiment it is found that solubility of potassium chloride i water is 10 moles per litre If we add 2 mole of potassium chloride to a litre of water Then which statement is correct for the following reaction SolveLancer Test KCl s H O NaCl aq a AG 0 AS 0 b AG 0 AS 0 c AG 0 AS 0 d AG 0 AS 0

5 The 22 solubility product of Agl at 25 C is 1 0 10 16 mol L 2 The solubility of Agl in 104 M solution of Kl at 25 C is approximately in mol L 1 1 0 10 16 2 1 0 10 12 3 1 0 10 10 4 1 0 10 8