IONIC EQULIBRIUM
Solubility product:
1. The Ksp value of AgCl depends on
1) solvent in which it is dissolved.
2) Temperature of solution.
3) Concentration of AgCl in the solution.
4) Amount of silver and chloride ions in the solution.
2. Solubilty product is
1) thermodynamic property.
2) kinetic property.
3) both.
4) none of the above
3. A beaker contains pure water. Then a sufficient amount of NaCl is added so that equilibrium is reached between dissolved solid(undissociated and dissociated). The equilibrium concentrations of Na+ is 5mol/lit. then find the Ksp of NaCl in water(in mol2/lit2)
5)1)5 2)10 3)30 4)25
4. Ksp of NaCl is less in ethanol when compared to water because
- lessser interactions in water compared to ethanol
- greater interactions in water compared to ethanol.
- just an observation
- does not depend on interaction
5. A solution contains a saturated amount of MCl2. The concentration of M+2 is 0.15mol/lit.
Assume amount of chloride in the solution only come from the MCl2. Then calculate the Ksp of solute.
1)0.125 2)0.225 3)0.00135 4)0.1
6. A beaker contains Ag+ ,Mn+2 ,Cu+2 ions at equal concentration of 0.1M. Slowly NaCl is added to the solution. Then find which salt precipitates first
1)AgCl 2)MnCl2 3)CuCl2.
4) all precipitate at the same time(where Ksp of the salts are 10-10,10-20,2*10-10)
7) Calculate the solubility of PbI2 in 0.1M KI (given complex formation constant of [PbI4]-2 =5x105, Ksp of the salt is 4x10-9)
1)2x10-3 2) 0.05M 3) 0.1M 4) 2x10-2
8) Calculate the solubility of CdS in 0.1M KCN solution. Given the Ksp of the CdS, Cd(CN)24x10-4 ,4x10-6 respectively.
1)2x10-3 2) 0.05M 3) 0.1M 4) 2x10-2
9) Ksp of MX and QX2 are 4x10-12. Then which is relatively more soluble
1.MX
2.QX2
3.Equally soluble
Common ion effect:
10.calculate the concentration of H+ ions in the solution of acetic acid. Where the dissociation constant of aceti acid is 10-5mol/lit. concentration of acetic acid =0.1M
1.0.11M 2.0.01M 3.0.001M 4.0.1M
11. calculate the concentration of H+ ions in the solution of HCl of concentration 10-7mol/lit.
1.10-7 2.2*10-6 3.1.6*10-7 4.10-6
12. Concentration of hydroxide ions in the water is after adding HCl is
1.10-8 2.0.5*10-7 3.0.618*10-7 4.10-7
13. To a saturated solution of AgCl a small amount of NaCl is added. Value of Ksp is 10-10mol2/lit2. Amount of chloride ions added is half to the concentration present in the solution before adding the ion. Then calculate the amount of Chloride ions in the solution after adding.
1)2*10-7 2)1.231*10-5 3)0.54*10-5 4.5*10-5
14. In the above question calculate the amount of sodium ions present in the solution after adding chloride ions.
1.0.731*10-5 2)1.231*10-5 3)0.54*10-5 4.5*10-5
15. Calculate the weight of AgCl precipitated after adding the chloride ions(in micro grams)
1.386 2.148 3.40 4.100
16. Calculate the H+ ions which are produced from the second dissociation reaction of 0.01M H3PO4. Given the equilibrium constants of the each reaction in order =(0.01,0.0005,0.000002)
1.0.01 2.0.005 3.0.00002 4.0.006180
17) Calculate the ratio of dissociations of 1M HX and 1M HY which are in the same solution(where dissociation constant of HX is double that of HY)
1.4
2.2
3.0.5
4.0.25
18) When NO2 is bubbled in water it,completelydisproportionates to give HNO2 and HNO3.
2NO2 + H2O→HNO2+HNO3. The concentration of NO2- in a solution prepared by dissolving 0.05mole of NO2 gas in 1 litre H2O is{Ka(HNO2)=5*10-4}
1)~5*10-4
(2) ~ 4.8 × 10–5
(3) ~ 4.8 × 10–3
(4) ~ 2.55 × 10–2
19)How many moles NH3 must be added to 2.0 litre of 0.80 M AgNO3 in order to reduce the Ag+ concentration to 5 × 10–8 M. Kf of [Ag(NH3)2+] = 108
(A) 0.4(B) 2(C) 3.52(D) 4
pH and buffer solutions:
21) 0.1M Na2CO3 is titrated with 0.1MHCl. Calculate the pH of the solution at the 1st equivalent point(i.e, point using phenopthalene)(pKa1 of H2CO3 is 2.5, pKa2 is 4.1)
1.3.3 2.2.5 3.5.5 4.6.6
22) Find the pH at the 2nd equivalent point(obtained using methyl orange)
1.3.5 2.2.5 3. 4 4.2
Questions 23 to 26 are to be done based on data provided here. In each case find the pH of the solution.
pKa1 of H2CO3 =3.5
pKa2 of H21CO3=5.6
pKa1,pKa2,pKa3 of H3PO4 is 2.5,4.5,6.8.
23) 50 ml of 0.12 M H3PO4 + 20 ml of 0.15 M NaOH
1.4.5 2. 5.5 3. 3.5 4.2.5
24)50 ml of 0.12 M H3PO4 + 40 ml of 0.15 M NaOH
1.6.8 2.3.5 3.4.5 4.5.5
25)40 ml of 0.12 M H3PO4 + 40 ml of 0.18 M NaOH
1. 2. 3 4.4.5
26)40 ml of 0.10 M H3PO4 + 40 ml of 0.25 M NaOH
1.2.5 2.6.5 3.5.5 4.6.8
27) pH of solution containing HCl is 6.95. then find the concentration of HCl in the solution
1.10-8 2.10-6 3.10-7 4.2.39*10-8
28) Human blood is a buffer of
1.CO2,H2CO3
2.H2CO3,HCO3-
3.HCO3-,CO2
4.NH3,NH4+
29) buffer capacity is equal to
1.d(pH)/dV
2.d(V)/d(pH)
3.d([H+])/dv
4.dv/d([H+])
30) Calculate the pOH of the solution obtained by mixing 10mL of 1MNaOH and 15mL of 1M AcOH(where the pKa of AcOH is 4.7)
1.5 2.9 3.10 4.11
31) 10mL of 0.1M AcOH is titrated with 0.1M NaOH. Find the volume of the solution at which the pH of the solution is 4.7.(given the pKa is 4.7)
1. 20ml2.15ml 3.25ml 4.10ml
32) A weak base BOH was titrated against a strong acid . The pH at 1/4th equivalence point was 9.24.Enough strong base was now added (6m.eq.) to completely convert the salt. The total volume was 50ml. Find the pH at this point.
1. 4 2. 4.81 3.8 4. 5.11
33. calculate the concentration of HPO4-2ion in the solution of 0.1 molar phosphoric acid(0.01,0.0005,0.00002)
1.0.001 2.0.0005 3.0.00002 4.0.002
34. Calculate the PH of the solution containing 0.1MCH3COONa, 0.1MCH3COOH where the Pkaof the acetic acid is 4.7
1.4.5 2.2.5 3. 2.6 4. 4.7
35. Calculate the pH of the solution which is obtained by adding 60g of oxalic acid to the 1lit of water. (pKa1=4.2, pka2=7.5)
1.10 2.5.5 3.5.8 2.1 4.
36) Calculate the pOH of the solution obtained by mixing 10mL of 1MNaOH and 15mL of 1M AcOH(where the pKa of AcOH is 4.7)
1.2 2.5 3.2 4.9
37) 10mL of 0.1M AcOH is titrated with 0.1M NaOH. Find the volume of the solution at which the pH of the solution is 8.6995.(given the pKa is 4.7)
1.20ml 2.30ml 3.15ml 4.20ml
38) A colour indicator changes colour significantly when the ratio of [In-]/[HIn] is 0.5, then find the pH at which the colour changes significantly(pKa = 4.5)
1. 1.5 2. 4.8013.4.7 4.4.5
39) Calculate the weight of NaOH required to add to a solution containing 1mol of AcOH such that we get a pH of solution equal to 4.8(pKa of acetic acid is 4.7).
1. 5.02.4.7 3.4.9 4.5.45
Hydrolysis of salts:
40.pKa of the acetic acid is 4.7. Find the pKb of the hydrolysis
1. 12 2. 10 3. 5.5 4.9.3
41. A solution contains 0.1MCH3COONa. Find the PH of the solution (take the necessary constants from previous question)
1. 7.5 2. 8.5 3. 5.8 4. 8.85
42. calculate the PH of the solution of 0.1mol/lit of HCl solution when titration is half completed with 0.1 mol/lit of NaOH solution.
1)3.5 2)2.5 3. 1.47 4)1.5
43. calculate the PH of the solution of 0.1mol/lit of AcOH solution when titration is half completed with 0.1 mol/lit of NaOH solution(Ka of acetic acid is 10-5mol/lit).
1. 2.5 2)5 3)3 4)5.5
44) Calculate the pH of 1M salt of Na2HPO4.(use values given in the paragraph)
1. 22. 53.5.65 4.10
45. Find the PH of the solution containing 0.1MBCl where BOH is a weak base the Pkb is 4.7
1.1.65 2. 6.5 3. 2.5 4.5.5
46) Calculate the pH of 1M CH3COONH4 (where the pKa and pKb are equal to 4.7)
1)10 2)7 3)12 4)5.5
Acids and bases:
47. Choose the right answer HCl,Cl-,HCN,CN-
1)Weak acid, weak base, strong acid, strong base
2)Strong acid, strong base, weak acid, weak base
3)Strong acid, weak base, weak acid, strong base
4)Weak acid, strong base, weak acid, weak base
48) Choose correct statements about BF3
1.Accept a H+
2.Lewis acid
3.Donate a lone pair of electrons
4.Releases H+ when dissolved in water
49. At 250C what is the equilibrium constant for the water dissociation reaction(for pure water)
1.10-14 2.1014*2 3. 2*10-14 4.1.8*10-15
50. PH of pure water at 750C is 6.5. then at this temperature what is the nature of water
1)Acidic
2)basic
3)neutral
4)cannot say.
51. Conjugate base of H2PO4- is
1)H3PO4
2)HPO4-2
3)H2PO4-
4)None of the above
52) temperature rise when we 10mL each of 0.1M solution of HCl and 0.1M NaOH is 10C. calculate the temperature rise when we mix 20mL of above both solutions
1)1 2)2 3)1.5 4)2.5
IONIC EQUILIBRIUM2
1. A solution contains 0.1M H2S and 0.3M HCl. Calculate the conc. Of S2- and HS- ions in the solution. Given Ka1 and Ka2 for H2S are 10-7 and 1.3*10-13 respectively.
1. 1.44*10-19 ,3.3*10-7
2.1.44*10-20 ,3.3*10-8
3.1.44*10-22, 3.3*10-3
4.1.44*10-18, 3.3*10-5
2. An aqueous solution of metal bromide MBr2(0.05M) is saturated with H2S. The minimum pH at which MS will ppt. will be
( Ksp for MS =6*10-21 concentration of saturated H2S =0.1, Ka1(H2S) =10-7 Ka2(H2S)=1.3*10-13)
1. 0.892 2.0.0983 3.1.96 4.2.96
3. The self ionization constant for pure formic acid, K=[HCOOH2+][HCOO-] has been estimated as 10-6 at the room temperature. What percent of the formic acid molecules in pure formic acid are converted to formate ion? The density of the formic acid is 1.22g/cc.
1.0.0037 2.0.037 3.0.37 4.1.037
4. An aqueous solution contains 10% ammonia by mass and has density of 0.99g/cc. the pH of this solution is[Ka = 5*10-10M.]
1)11.033 2)12.033 3)9.033 4)7.2033
5. At 250C,pH of a solution of a monobasic acid [HA] is 4.The correct statements regarding HA and its given solution is(are)
1. HA is weak acid.
2. The ionization constant of acid is approximately 10-6 at 250C.
3. Increasing the temperature of solution would cause the pH to decrease.
4. Addition of 0.1M HCl solution would lower pH by increasing degree of ionization.
6. Which of the following mixtures will have pH closest to 1.0?
1. 100mL M/10 HCl and 100 M/10 NaOH
2.160mL 0.075M H2SO4 + 40mL M/10 NaOH
3. 55mL M/10 HCl + 45mL M/10 NaOH
4. 75mL M/5 HCl +25mL M/5 NaOH
7. The equilibrium constant for the reaction of a weak acid HA with strong baseNaOH is 1 at 250C. Which of the following deductions are correct?
1. The ionization constant at 250C is 10-5 for HA.
2. pH of a 0.01M aqueous solution of HA at 250C.
3. pH of a 0.10M aqueous solution of NaA at 250C will be 9.
4. If Kb of a weak base BOH is 10-4 at 250C., equilibrium constant for neutralization of HA with BOH at 250C will be 105.
8. If 500mL of 0.4M AgNO3 is mixed with 500Ml of 2M NH3 solution then what is the concentration of [Ag(NH3)]+ in solution( Kf1[[Ag(NH3)]+]=103, Kf2 [Ag(NH3)2]+ =104)
1. 3.33*10-7M 2.3.33*10-5M. 3.3*10-4M. 4.10-7M.
9. Solution of X is being titrated against a solution of Y. If phenolphthalein is found to be a suitable indicator, X and Y could be respectively.
1.NaOH and HCl 2.HCl and NaOH
3. CH3COOH and NaOH 4. HCl and NH3
10. Two sparingly soluble salts AX and BX2 have their solubility product constants equal. Which of the following statements is(are) correct deduction.
1. solubility of AX is greater than solubility of BX2.
2. If S1 and S2 are molar solubility of AX and BX2 then S1=(S2)3/2.
3. If X is a conjugate base of a weak acid, addition of HNO3 will increase solubility of both AX and BX2.
4. Increasing the temperature,increase the solubility of both AX and BX2.
11. An indicator(HIn) has its ionization constant 5*10-5 at 250C. Also its acid form is deep orange while its basic form is yellow coloured in the aqueous solution. Which of the following are true regarding this indicator.
1. the working pH of indicator is 3.3 to 5.3
2. It would be appropriate indicator for titration of 0.1M HCl with 0.1M NaOH solution
3. If an acid is being titrated using this indicator, at the end point of solution changes from yellow to orange.
4. It can also be used in the titration of CH3COOH(Ka =2*10-5) with NaOH.
12. Which of the following is true about an aqueous solution(saturated) of AgCl?
1. Adding AgCl lowers solubility of AgCl.
2. Adding Na2CO3 has no effect.
3. Adding aqueous ammonia increases solubility of AgCl.
4. Adding NaBr doesn`t affect the solubility of AgCl.
13. Ksp of Ag2CrO4 is 4*10-12. Which of the following mixing will bring about precipitation of Ag2CrO4.
1. 10mL 3*10-4M AgNO3 + 10mL 10-4M NaCrO4
2. Adding 10mmol NaCrO4 to 100mL saturated AgCl solution.
3.mixing equal volumes of 10-4M AgNO3 with 10-4M Na2CrO4 solution.
4. 10mL 10-3M AgNO3 +15mL 10-3M Na2CrO4.
14. Which of the following statements is(are) correct?
1. The conjugate acid of NH2- is NH3.
2. Ksp increases with increase in concentration of ions.
3. On the dilution of a buffer solution, pH change is negligible.
4. In alkaline buffer solution, if some HCl is added it`s [OH-] will increase.
15. Formic acid is a weak acid and HCl is a strong acid. It follows that the
1. [OH-] of 0.01M HCl will be less than that of 0.01M HCOOH
2. Solution containing 0.2M NaOH and 0.1M HCOONa is a buffer solution.
3. pH of 10-9M HCl will be approximately 7 at 250C.
4. pH of a solution formed by mixing equimolar quantities of HCOOH and HCl will be less than that of a similar solution formed from HCOOH and HCOONa.
Integer type questions:
16. A 200mL of 5*10-5 M HCl solution is mixed with another 300mL 5*10-5 M NaOH solution at 250C. Assuming temperature to be constant, pH of the resulting solution is
17. A buffer solution is formed by mixing 100mL 0.01M CH3COOH with 200mL 0.02M CH3COONa. If this buffer solution is made to 1.0L by adding 700mL of water, pH will change by a factor of
18. If the equilibrium constant of the reaction of a weak acid HA with a strong base is 109, then pH of 0.1M NaA solution is
19. Solubility product constant of a sparingly soluble salt MCl2 is 4*10-12 at 250C, solubility of MCl2 is an aqueous solution of CaCl2 is 4*108 times less compared to its solubility in pure water . Hence, concentration of CaCl2 solution is
20. The solubility product constant of a metal carbonate MCO3 is 2*10-12 at 250C. A solution is 0.1m in M(NO3)2 and it is saturated with 0.01M CO2. Also the ionization constant of CO2 are: Ka1=4*10-7 and Ka2 =5*10-11 at 250C. The minimum that must be maintained to start the any precipitation is
21. The total no:of diprotic acids among the following is
H3PO4, H2SO4, H3PO3, H2CO3, H2S2O7, H3BO3, H3PO2, H2CrO4, H2SO3
22.The sum of basicities of H3PO4, H3PO3 and H3PO2 is
23.Ksp of M(OH)2 is 5*10-16 at 250C. The pH of its saturated solution is 24. The pKa1 and pKa2 of an amino acid are 2.3 and 9.7 respectively. The isoelectric point of amino acid is
25.In 1L saturated solution of AgCl (Ksp=1.6*10-6), 0.1mole of CuCl (Ksp=1.0*10-6) is added.. The resultant concentration of Ag+ in the solution is 1.6*10-x, then value of x is
26. Conjugate base of [Al(H2O)6]3+ is [Al(H2O)x(OH)y]3-y the value of x/y is
27. The pH of a beaker A is 2.8. The pOH of beaker B is 8.4. find the ratio of [H+] of A /[H+] of B is
COMPREHENSION TYPE QUESTIONS
Questions(28-)
The solution which consumes [H+] or [OH+] or both simultaneously from externally added base inorder to give negligible change in pH is known as buffer solution. In general, the solution resists the change in pH. Buffer solution does not mean that does not occur a pH change at all. It implies the pH change occurs but in negligible amount. These are types of buffers
- Acidic buffer
- Basic buffer
28. Which of the following mixture will be a buffer solution when dissolved in 500mL of water?
1)0.200mol of aniline and 0.200 mol of HCl
2) 0.200mol of aniline and 0.400 mol of NaOH
3)0.200 mol of NaCl and 0.100 mol of HCl
4) 0.200 mol of aniline and 0.100mol of HCl
29.pH of 0.01M (NH4)2SO4 and 0.02M NH4OH buffer(pKa of NH4+ =9.26)
1) 4.74+log2 2) 4.74-log2 3) 4.74+log1 4) 9.26+log2
30) To prepare the buffer of pH 8.26, amount of (NH4)2SO4 to be added into 500mL of 0.01M NH4OH solution
1) 0.05mol 2) 0.025mol 3) 0.01mol 4) 0.005mol
Questions(31-)
Acid base indicators are either weak acids or weak bases. Indicator change colour in dilute solution when the pH of the solution reaches a particular value. For, example phenolphthalein is a colour less substance in any aqueous solution with pH less than 8.3, in between 8.3 to 10, colour changes and if pH is greater than 10 it is pink in colour. considering the acid indicator HIn ,the equilibrium involving it and it`s conjugate base In- can be represented as:
HIn↔H++In-
pH can be calculated by using the equation
pH=pKa+log[In-]/[HIn]
in general transition takes place in between the pH range pKIn ±1.
31) An indicator is a weak acid and pH range is 4.0 to 6.0. if indicator is 50% ionized in a given solution then what is the ionization constant of the acid?
1. 10-4 2. 10-5 3.10-6 4. 10-7
32.select the correct statements among the following
1) In the complete ionization of indicator its pH=pKin
2) Methyl orange(range 3.1 to 4.4) is a suitable indicator for weak acid and strong base.
3) Bromothymol blue(range 6.0 To 7.6) is a good indicator for titration of HCl and NaOH.
4) Thymol blue (range 1.2 to 2.8) is good indicator for titration of 100mL of 0.1M NH4OH and 0.1M HCl
33. The ionization constant of an indicator is 5*10-5 at 250C. Its acid form is deep orange while its basic form is yellow in colour in aqueous solution. Which of the following statements is true for this indicator?
1) The working range of indicator is 3.3 to 5.3
2) it cannot be used in the titration of 0.1M HCl and 0.1M NaOH.
3) If an acid is titrated using this indicator at end point colour of solution changes from yellow to orange.
4) It can be used an indicator in titration of CH3COOH.
34) If an indicator is to be used in an acid base titration having an equivalent point in pH range 8 to 10, the indicator must
1) be a weak base
2) haveKa of about 10-9
3) ionize in two steps.
4) be added to the solution only after it became alkaline.
35) which of the following indicator is most suitable for titration of HB with strong base:
1) phenolphthalein(8.3-10)
2) Bromothymol blue(6-7.6)
3) methyl red(4.2-6.3)
4) malachite green(11.4-13)
36) How can you find the end point from the graph which shows pH vs volume added?
1) mid point of the ends.
2) point at which slope is 450
3) point at which slope is 900
4) none of the above.
37) The salt Al(OH)3 is involved in the following two equilibria,
Al(OH)3↔Al+3 + 3OH- , Ksp;
Al(OH)3 + OH- ↔ Al(OH)4-, Kc;
Which of the following relationship is correct at which solubility is minimum?
1) [OH-]=(Ksp/Kc)1/3 2) [OH-]=(Kc/Ksp)1/4 3) [OH-]=(Ksp/Kc)1/8
4) [OH-]=(3Ksp/Kc)1/4
38) AgBr+2S2O32-↔[Ag(S2O3)]2-+Br-[ Ksp of AgBr=5*10-13, Kf[[Ag(S2O3)]2- =5*1013]. What is the molar solubility of AgBr is 0.1M Na2S2O3?
1) 0.5M 2)0.45M 3)0.045M 4) 0.65M
39) The pH of the pure water at 250C and 350C are 7 and 6 respectively. The heat of formation of water from H+ and OH- will be (in Kcal/mol)
1) +84.551 2)-84.551 3)+8.4551 4)-8.4551
40) Aqueous solution of HNO3, KOH, CH3COOH and CH3COONa of identical concentrations are provided. The pairs of solutions which upon mixing produces buffer solution is/are
1) HNO3 and CH3COONa
2) KOH and CH3COONa
3) HNO3 and CH3COONa
4)CH3COONa and CH3COOH
41) which of the following describes the following titration curve?
1)A strong base is added to strong acid
2) A strong base is added to weak acid
3) A weak base is added to strong acid
4) A weak base is added to weak acid.
MATRIX MATCHING:
42) Match the salt with its equation of pH
Column I
A) weak acid and strong base
B) strong acid and weak base
C) weak acid and weak base
D) strong acid and strong base
Column II
P) 1/2pKw
Q)1/2[pKw+pKa-pKb]
R)1/2[pKw-pKa-logC]
S)1/2[pKw+pKa+logC]
43) In the titration of weak acid against strong base match the pH of the solution at different stages of titration.
Column I
A) 0%
B)50%
C)100%
D)>100%
Column II=pH
P) 7+ 1/2pKa+1/2logC
Q)14+log[OH-]
R) 1/2pKa-1/2logC
S) pKa+log([salt]/[acid])