MCQ Questions Chapter 7 Equilibrium Class 11 Chemistry

Please refer to MCQ Questions Chapter 7 Equilibrium Class 11 Chemistry with answers provided below. These multiple-choice questions have been developed based on the latest NCERT book for class 11 Chemistry issued for the current academic year. We have provided MCQ Questions for Class 11 Chemistry for all chapters on our website. Students should learn the objective based questions for Chapter 7 Equilibrium in Class 11 Chemistry provided below to get more marks in exams.

Chapter 7 Equilibrium MCQ Questions

Please refer to the following Chapter 7 Equilibrium MCQ Questions Class 11 Chemistry with solutions for all important topics in the chapter.

MCQ Questions Answers for Chapter 7 Equilibrium Class 11 Chemistry

Question. The pK_a of a certain weak acid is 4.0. What should be the [salt] to [acid] ratio if we have to prepare a buffer with pH = 5 using the acid, and one of the salts ? 
(a) 10: 1
(b) 1 : 10
(c) 4: 5
(d) 5: 4       

Question. 20 mL 0.1 N acetic acid is mixed with 10 mL 0.1 N solution of NaOH. The pH of the resulting solution is (pK_a of acetic acid is 4.74)
(a) 3.74
(b) 4.74
(c) 5.74
(d) 6.74     

Question. A buffer solution contains 0.1 mole of sodium acetate dissolved in 1000 cm³ of 0.1 M acetic acid. To the above buffer solution, 0.1 mole of sodium acetate is further added and dissolved. The pH of the resulting buffer is 
(a) pK_a
(b) pK_a + 2
(c) pK_a – log 2
(d) pK_a + log 2   

Question. Which of the following is not a buffer solution?
(a) 100 mL 0.1 M CH₃COOH + 50 mL 0.1 M CH₃COONa
(b) 100 mL 0-lM CH₃COOH+ 50 mL 0-lM NaOH
(c) 50 mL 0.1 M CH₃COOH + 100 mL 0.1 M NaOH
(d) 100 mL 0.1 M NH₄OH + 50 mL 0.1 M HCl       

Question. For the titration of solution of oxalic acid and sodium hydroxide, the suitable indicator is
(a) phenolphthalein
(b) methyl orange
(c) any of these
(d) None of these       

Question. A 100 mL of 0.1 M solution of ammonium acetate is diluted by adding 100 mL of water. The pH of the resulting solution will be (pK_a of acetic acid is nearly equal to pK_b of NH₄ OH) 
(a) 4.9
(b) 5.0
(c) 7.0
(d) 10.0       

Question. 2.5 mL of 2/5 M weak monoacidic base (K_b = 1 x 10^-12 at 5 25°C) is titrated with 2/15 M HCI in water at 25°C. The concentration of H⁺ at equivalence point is (K_w = 1 X 10^{– 14} at 25°C)
(a) 3.7 x 10^-13 M
(b) 3.2 x 10^-7 M
(c) 3.2 x 10^-2 M
(d) 2.7 x 10^-2 M       

Question. A buffer solution is prepared by mixinng equal concentration of a weak base with its salt of strong acid.K_b for the base is 10^-9 . pH of this buffer solution will be
(a) 9
(b) 4
(c) 5
(d) 13     

Question. Calculate the pH at the equivalence point during the titration of 0.1 M, 25 mL CH3 COOH with 0.05 M NaOH solution.[K0 (CH₃COOH) = 1.8 x 10^-5] 
(a) 9.63
(b) 8.63
(c) 10.63
(d) 11.63   

Question. One mole of ammonia was completely absorbed in IL solution each of
I. I MHCI
II. I M CH₃COOH and
III. I M H₂SO₄ at 298 K
The decreasing order for the pH of the resulting solution is (given, K_b (NH₃) = 4.74) 
(a) II> III > I
(b) I >II> III
(c) II> I > III
(d) III> II> I     

Question. Which is the best choice for weak base-strong acid titration? 
(a) Methyl red
(b) Litmus
(c) Phenol red
(d) Phenolphthalein         

Question. The aqueous solutions of HCOONa, C₆H₅NH₃CI and KCN are respectively 
(a) acidic, acidic, basic
(b) acidic, basic, neutral
(c) basic, neutral, neutral
(d) basic, acidic, basic       

Question. In the titration of NaOH and HCl, which of the following indicator will be used ?
(a) Methyl orange
(b) Methyl red
(c) Both (a) and (b)
(d) None of these   

Question. An acidic buffer solution could be prepared by mixing the solutions of the following 
(a) sodium acetate and acetic acid
(b) ammonium sulphate and sulphuric acid
(c) ammonium chloride and ammonium hydroxide
(d) sodium chloride and hydrochloric acid     

Question. A buffer solution is prepared by mnong equal concentration of acid (ionisation constant Ka ) and a salt. The pH of buffer is
(a) pK_a + 7
(b) 14 – pK_a
(c) pK_a
(d) pK_a + I   

Question. The pH of an aqueous solution CH₃COONa of concentration C(M) is given by of 
(a) 7- 1/2 pK_a – 1/2 Iog C
(b) 1/2 pK_w + 1/2 pK_b + 1/2 loge
(c) 1/2 pK_w – 1/2 pK_b – 1/2 loge
(d) 1/2 pK_w + 1/2 pK_a + 1/2 loge     

Question. A strong acid is titrated with weak base. At equivalence point, pH will be 
(a) < 7
(b) > 7
(c) = 0
(d) cannot predict       

Question. pH of an acid buffer is given by 
(a) pH = pK_a + log [salt]/[acid]
(b) pH = pK_a – log [salt]/[acid] 
(c) pH = K_a + log [salt]/[acid]
(d) Noneofthese   

Question. The pK_a ofa weak acid, HA, is 4.80. The pK _b of a weak base, BOH is 4.78. The pH ofan aqueous solution of the corresponding salt, BA, will be 
(a) 9.58
(b) 4.79
(c) 7.01
(d) 9.22       

Question. Which one of the following salts will produce an alkaline solution while dissolving in water? 
(a) NH₄Cl
(b) Na₂CO₃
(c) NaNO₃
(d) Na₂SO₄       

Question. The compound whose 0.1 M solutions is basic, is 
(a) ammonium acetate
(b) ammonium chloride
(c) ammonium sulphate
(d) sodium acetate     

Question. Solid Ba (NO₃)₂ h is gradually dissolved in a 1.0 x 10^-4 M Na₂CO₃ solution. At what concentration of Ba²⁺ will a precipitate begin to form? (K_sp for BaCO₃ = 5.1 x 10^-9)
(a) 4.1 x 10^-5 M
(b) 5.1 x 10^-5 M
(c) 8.1 x 10^-8 M
(d) 8.1 x 10^-7 M       

Question. In qualitative analysis, in m group NH₄Cl is added before NH₄OH because 
(a) to increase the concentration of NH⁺₄ ions
(b) to increase the concentration of Cl^– ions
(c) to reduce the concentration of OH^– ions
(d) to increase the concentration of OH^– ions     

Question. Approximate relationship between dissociation constant of water (K) and ionic product of water (K_w) is 
(a) K_w =K
(b) K_w = 55.6 x K
(c) K_w =I8 x K
(d) K_w = l4 x K   

Question. The solubility product of iron (ID) hydroxide is 1.6x 10^{– 39} . If Xis the solubility of iron (III) hydroxide, then which one of the following expressions can be used to calculate X ?
(a) K_sp = X ⁴
(b) K_sp = 9X⁴ 
(c) K_sp = 27X³
(d) K_sp = 27X⁴     

Question. Addition of sodium acetate to 0.1 M acetic acid will cause
(a) increase in pH 
(b) decrease in pH
(c) no change in pH
(d) change in pH that cannot be predicted     

Question. The solubility of AgCl in 0.2 M NaCl is (K_sp of AgCl = 1.8 X 10^-10)
(a) 1.8 x 10^-11 M
(c) 6.5 x 10^-12 M
(b) 9 x 10^-10 M
(d) 5.6 x 10^-11 M     

Question. Solubility product of Mg (OH)₂ at ordinary temperature is 1.96 x 10^-11 . pH of a saturated solution, of Mg(OH)₂ will be
(a) 10.53
(b) 8.47
(c) 6.94
(d) 3.47     

Question. An aqueous solution contains Ni²⁺ , CO²⁺ and Pb²⁺ ions at equal concentrations. The solubility Eroduct of NiS, PbS and Cos in water at 25°C are 1.4 X 10^-24, 3.4 X 10^-28 and 3 x 10^-26, respectively. Indicate which of these ions will be precipitated first and last when sulphide concentration is progressively increased from zero? 
(a) NiS and PbS
(b) NiS and CoS
(c) CoS and NiS
(d) PbS and NiS       

Question. Solubility product of a salt AB is 1 x 10^-8 M² in a solution in which the concentration of A⁺ ions is 10_-3 M. The salt will precipitate when the concentration of B^– ions is kept
(a) between 10^-8 to 10^-7 M
(b) between 10^-7 M to 10^-8 M
(c) > 10^-5 M
(d) < 10^-8 M       

Question. Solubility product constant [K _sp] of salts of types MX, MX₂ and M₃X at temperature T are 4.0x 10^-8 , 3.2 x 10^-14 and 2.7x 10^-15 respectively. Solubilities (mol, dm^-3) of the salts at temperature T are in the order
(a) MX > MX₂ > M₃X 
(b) M₃X > MX₂ >MX
(c) MX₂ > M₃X > MX
(d) MX > M₃X > MX₂     

Question. Solubility of Ca(OH)₂ is a s mol L^-1 . The solubility product (K _sp) under the same condition is 
(a) 4s³
(b) 3s⁴
(c) 4s²
(d) s³     

Question. In a saturated solution of the sparingly soluble strong electrolyte AglO₃ (molecular mass = 283) the equilibrium which sets in is 
                   AgIO₃ (s) ⇌ Ag⁺ (aq)+IO^–₃(aq)
 If, the solubility product constant K _sp of AglO₃ at a given temperatw·e is 1.0 x10^-8, then what is the mass of AgIO₃ contained in 100 mL of its saturated solution? 
(a) 28.3 X 10^-2 g
(b) 2.83 X 10^-3 g
(c) 1.0 X 10^-7 g
(d) 1.0 X 10^-4 g     

Question. The solubility of AgCI is 1 x 10^-5 mol/L. Its solubility in 0.1 molar sodium chloride solution is 
(a) 1 X 10^-10
(b) 1 X 10^-5
(c) 1 X 10^-9
(d) 1 X 10^-4       

Question. Solubility of AgCI at 20°c is 1.435 x 10^-3 g/ L. The solubility product of AgCl is
(a) 1 X 10^-5
(b) 1 X 10^-10
(c) 1.435 X 10^-5
(d) 108 X 10^-3     

Question. At 30°C, the solubility of Ag₂CO₃ (K_sp = 8 x 10-12) would be greatest in I L of 
(a) 0.05 M Na₂CO₃
(b) 0.05 M AgNO₃
(c) pure water
(d) 0.05 M NH₃       

Question. TbepKa ofa weak acid HA is 4.5. ThepOHofanaqueous buffered solution of HA in which 50% of the acid ionised is
(a) 4.5
(c) 9.5
(b) 2.5
(d) 7.0     

Question. Which one of the following salts on being dissolved in water gives pH > 7 at 25°C ? 
(a) KCN
(b) KNO₃
(c) NH₄Cl
(d) NH₄CN   

Question. The pH of a buffer solution contammg equal molal concentration of a weak base and its chloride (Kb for weak base = 2 X 10^-5 ) is 
(a) 5
(b) 9
(c) 4.7
(d) 9.3     

Question. Relation between hydrolysis constant and dissociation constant are given. Which is the correct formula for MgC12? 
(a) K_h, = K_w/K_a
(b) K_h = K_w/K_b
(c) K_h,= K_w/  K_a X K_b
(d) K_w = K_h/K_b       

Question. The rapid change of pH near the stoichiometric point of an acid base titration is the basis of indicator detection. pH of the solution is related to the ratio of the concentrations of the conjugate acid (Hin) and base (In^–) forms of the indicator given by the expression 
(a) log [In^–]/[Hln] = pK_in – pH
(b) log [Hin]/[In^–] = pK_in – pH 
(c) log [Hln]/[In^–] = pH – pK_in
(d) log [In^–]/[Hln] = pH – pK_in       

Question. The hydrolysis of sodium carbonate involves the reaction between 
(a) sodium ion and water
(b) Na⁺ and OH^–
(c) CO₃^2- and water
(d) CO₃^2- and H⁺   

Question. In the titration of NaOH and HCl, which of the following indicator will be used ?
(a) Methyl orange
(b) Methyl red
(c) Both (a) and (b)
(d) None of these   

Question. An acidic buffer solution could be prepared by mixing the solutions of the following 
(a) sodium acetate and acetic acid
(b) ammonium sulphate and sulphuric acid
(c) ammonium chloride and ammonium hydroxide
(d) sodium chloride and hydrochloric acid     

Question. Which one of the following pair shows buffer’s solution?
(a) NaCl + NaOH 
(b) CH₃COONa + CH₃COOH
(c) CH₃COOH + CH₃COONH₄
(d) H₂SO₄ + CuSO₄     

Question. A buffer solutfon has equal volumes of 0.2 M NH₄OH and 0.02 M NH₄CL The pK_b of the base is 5. The pH is equal to 
(a) 10
(c) 4
(b) 9
(d) 7       

Question. For the reaction, SO₂ (g) + 1/2 O₂ (g) ⇌ SO₃ (g) if,K_P =K_c (RT)^x where, the symbols have usual meaning, then the value of x is (assuming ideality) 
(a) –1 
(b) –1/2
(c) –1/2
(d) 1   

Question. The rate constant for forward reaction and backward reaction of hydrolysis of ester are 1.1 x 10^-2 and 1.5 x 10^-3 per minute, respectively. Equilibrium constant for the reaction 
    CH₃COOC₂H₅ + H₂O ⇌ CH₃COOH + C₂H₅OH is
(a) 33.7
(b) 7.33
(c) 5.33
(d) 33.3   

Question. Equal moles of NO₂ (g) and NO (g) are to be placed in a container to produce N₂O. 
According to the reaction,
           NO2 +NO ⇌ N₂O + O₂ ,K_c = 0.914
How many moles of NO₂ and NO be placed in the 5.0 L container to have an equilibrium concentration of N₂O to be 0.05 M ? 
(a) 0.511
(b) 0.1023
Questionc) 0.0526
QuestionQuestiond) 0.2046   

Question. For the equilibrium reaction
     CaCO₃ (s) ⇌ CaO(s)+CO₂ (g),
         K_P = l.64 atrn at 1000 K
50 g of CaCO₃ in a 10 L closed vessel is heated to 1000 K. Percentage of CaCO₃ that remains unreacted at equilibrium is [given, R = 0.082 L atrn K^-1 mol^-1]
(a) 40
(b) 50     
(c) 60
(d) 20   

Question. The KP value for the reaction, H₂ + I₂ ⇌ 2HI at 460°C is 49. If the initial pressure of both H₂ and I₂ is 0.5 atrn, then what will be the partial pressure of H₂ at equilibrium ? 
(a) 0.112 atrn
(b) 0.123 atrn
(c) 0.113 atrn
(d) 0.222 atrn   

Question. In a reaction A + B ⇌ C + D, 40% of B has reacted at equilibrium, when 1 mole of A was heated with 1 mole of B in a 10 L closed vessel. The value of K_c is
(a) 0.44
(b) 0.18
(c) 0.22
(d) 0.36   

Question. The mixture of reactants and products in the equilibrium state is called 
(a) chemical mixture
(b) equilibrium mixture
(c) chemical equilibrium
(d) dynamic equilibrium     

Question. The initial rate of hydrolysis of methyl acetate (lM) by a weak acid (HA, l M) is 1/100th of that of a strong acid (HX, 1 M), at 25°C. The K_a HA is equal to
(a) 1 X 10^-4
(b) 1 X 10^-5 
(c) 1 X 10^-6
(d) 1 X 10^-3     

Question. K_P and K_c are related as
(a) K_P = K_c (RT)^Δn      
(b) K_c = K_P (RT)^Δn
(c) K_P + Kc = (RT)^Δn
(d) K_c = K_P   

Question. In the synthesis of ammonia 
        N₂ (g) + 3H₂ ⇌ 2NH₃ (g)
When 100 mL of N₂ has reacted, the volume of H₂ which has also reacted and ammonia produced are
(a) 300 mL H₂ and 200 mL NH₃
(b) 300 mL H₂ and 300 mL NH₃
(c) 100 mL H₂ and 100 mL NH₃
(d) 100 mL H₂ and 200 mL NH₃   

Question. Aquantity of PCl₅ was heated in a 10dm³ vessel at 250°C 
PCl₅(g) ⇌ PCl₃(g) + Cl₂(g)
At equilibrium, the vessel contains 0.1 mole of PCl₅ and 0.2 mole of Cl₂ . The equilibrium constant of the reaction is 
(a) 0.05
(b) 0.02
(c) 0.025
(d) 0.04     

Question. The equilibrium constant (K_c ) for the reactions N₂(g) + O₂(g) → 2NO(g) at temperature T, is 4 x 10^-4 . The value of K_c for the reaction NO(g) → 1/2 N₂ (g) + 1/2 O₂ (g)  at the same temperature is
(a) 0.02
(b) 2.5 X 10²
(c) 4 x 10^-4
(d) 50.0       

Question. For 2NOBr (g) ⇌ 2NO(g) + Br₂ (g ), at equilibrium Psr ₂ = p/9 and p is the total pressure, the ratio K_P/9 will be 
(a) 1 / 3
(b) 1/ 9
(c) 1 / 27
(d) 1/ 81     

Question. For the reaction, 1
        2NO₂ (g) + 1/2 O₂ ⇌ N₂O₅ (g)
if the equilibrium constant is K_P, then the equilibrium constant for the reaction would be
   2N₂O₅ (g) ⇌ 2N₂O₄ + O₂(g) 
(a) K²_p
(b) 2/K
(c) 1/K²_p
(d) 2k_p       

Question. The equilibrium constant of a reaction is 0.008 at 298 K. The standard free energy change of the reaction at the same temperature is
(a) – 11.96 kJ
(b) – 5.43 kJ
(c) – 8.46kJ
(d) + 11.96kJ       

Question. The correct o  rder of equilibrium constant for the reactions is
                  H₂CO + H₂O ⇌^K₁ H₂C(OH)₂ 
       CH₃CH₂CHO+       A H₂O ⇌^K2 CH₃CH₂CH(OH₎₂
           CH₃COCH₃ + H₂O ⇌^K3 CH₃C(OH)₂ CH₃
(a) K₁ > K₂ > K₃
(b) K₁< K₂ < K₃
(c) K₁ > K₃ > K₂
(d) K₁ < K₃ < K₂         

Question. A vessel at 1000 K contains CO₂ with a pressure of 0.5 atrn. Some of the CO₂ is converted into CO on the addition of graphite. If the total pressure at equilibrium is 0. 8 atm, then the value of KP is 
(a) 1.8 atrn
(b) 3 atm
(c) 0.3atm
(d) 0.18atrn     

Question. Assertion (A) The pH of a buffer solution containing equal moles of acetic acid and sodium acetate is 4.8 (pK_u O of acetic acid is 4.8). 
Reason (R) The ionic product of water at 25°C is 10^-14 mol² L^-2 . The correct answer is
(a) Both A and Rare true and R is the correct explanation of A.
(b) Both A and R are true and R is not the correct explanation of As.
(c) A is true but R is not true.
(d) A is not true but R is trne.       

Question. A buffer solution is prepared by mixing 0.1, M ammonia and 1.0 M ammonium chloride. At 298 K, the pK_b of NH₄OH is 5.0. The pH of the buffer is 
(a) 10.0
(b) 9.0
(c) 6.0
(d) 8.0       

Question. Which of the following salt does not get hydrolysed in water ? 
(a) KClO₄
(b) NH₄Cl
(c) CH₃COONa
(d) None of these       

Question. Amongst the following, the total number of compounds whose aqueous solution turns red litmus paper blue is 
KCN            K₂SO₄       (NH₄)₂C₂O₄        NaCl
Zn (NO₃)₂    FeCl₃         K₂CO₃              NH₄NO₃
LiCN
(a) 1
(b) 2
(c) 3
(d) 4     

Question. Which buffer solution comprising of the following has its pH value greater than 7 ? 
(a) CH₃COOH+CH₃COONa
(b) HCOOH + HCOOK
(c) CH₃COONH₄
(d) NH₄OH+ NH₄Cl       

Question. Assertion (A) The aqueous solution of CH₃COONa is alkaline in nature.
Reason (R) Acetate ion undergoes anionic hydrolysis.
(a) Both A and R are correct and R is the correct explanation of A
(b) Both A and R are correct but R is not the correct explanation of A
(c) A is correct but R is not correct
(d) A is not correct but R is correct       

Question. The buffering action of an acidic buffer is maximum when its pH is equal to 
(a) 5
(b) 7
(c) 1
(d) pK_a         

Question. A white substance having alkaline nature in solution is
(a) NaNO₃
(b) NH₄Cl
(c) Na₂CO₃
(d) Fe₂O₃   

Question. A solution of FeCl₃ in water acts as acidic solution due to 
(a) hydrolysis of Fe³⁺
(b) acidic impurities
(c) dissociation
(d) ionisation     

Question. 0.1 mole of CH₃NH₂ (K_b = 5 x 10^-4 ) is mixed with 0.08 mole ofHCl and diluted to IL. What will be the H⁺ concentration in the solution ? 
(a) 8 x 10^-2 M
(b) 8 x 10^-11 M
(c) 1.6 x 10^-11 M
(d) 8 x 10^-5 M     

Question. In the titration of Na₂CO and HCl, the indicator used is
(a) methyl orange 
(b) methylene blue
(c) phenolphthalein
(d) litmus   

Question. Degree of hydrolysis ( h) of a salt of weak acid and a strong base is given by 
(a) h = √K_h
(b) h = √C/K_h
(c) h = √K_h /C
(d) None of these   

Question. In a mixture of acetic acid and sodium acetate the ratio of concentration of the salt to the acid is increased ten times. Then, the pH of the solution 
(a) increases by one
(b) decreases by one
(c) decreases ten fold
(d) increased ten fold       

Question. Consider the following solutions of equal concentrations
A = NH₄CI
B = CH₃COONa
C = NHpH
D = CH₃COOH        
A buffer solution can be obtained by mixing equal volumes of 
(a) CandD
(b) A andB
(c) A and C
(d) C and D   

Question. What volwne of M/10 NaOH added in 50 mL, M/10 acetic acid solution to get a buffer solution having highest buffer capacity ? 
(a) 50 mL
(b) 25 mL
(c) 10 mL
(d) 40 mL     

Question. Which one of the following salts give an acidic solution in water ?
(a) CH₃COONa
(c) NaCl
(b) NH₄Cl
(d) CH₃COONH₄       

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