MCQ Questions Chapter 7 Equilibrium Class 11 Chemistry

Please refer to Equilibrium MCQ Questions Class 11 Chemistry below. These MCQ questions for Class 11 Chemistry with answers have been designed as per the latest NCERT, CBSE books, and syllabus issued for the current academic year. These objective questions for Equilibrium will help you to prepare for the exams and get more marks.

Equilibrium MCQ Questions Class 11 Chemistry

Please see solved MCQ Questions for Equilibrium in Class 11 Chemistry. All questions and answers have been prepared by expert faculty of standard 11 based on the latest examination guidelines.

MCQ Questions Class 11 Chemistry Equilibrium

Question. What is the best description of the change that occurs when Na₂O(s) is dissolved in water? 
(a) Oxidation number of sodium decreases
(b) Oxide ion accepts sharing in a pair of electrons
(c) Oxide ion donates a pair of electrons
(d) Oxidation nwnber of oxygen increases   

Question. At a certain temperature, the dissociation constants of formic acid and acetic acid are 1.8 x 10^-4 and 1.8 x l0^-5, respectively. The concentration of acetic acid solution in which the hydrogen ion has the same concentration as in 0.001 M fomlic acid solution is equal to 
(a) 0. 01 M
(b) 0. 001 M
(c) 0. lM
(d) 0. 0001M   

Question. Diacidic base is
(a) CH₂(OH)₂
(b) Ca(OH)₂
(c) CH₃CH(OH)₂
(d) All of these     

Question. Which is Lewis acid? 
(a) BF₃
(b) NF₃
(c) CI^–
(d) H₂O     

Question. A weak monobasic acid is 1 % ionised in 0.1 M solution at 2S’C. The percentage of ionisation in its 0.025 M solution is 
(a) 1
(b) 2
(c) 3 
(d) 4    

Question. Which of the following is the weakest acid? 
(a) HCl
(b) HF
(c) H₂SO₄
(d) HNO₃     

Question. According to hard and soft acid-base principle, a hard acid
(a) has low charge density 
(b) shows preference for soft bases
(c) shows preference for donor atoms of low electronegativity
(d) is not polarisable       

Question. Four species are listed below
I. HCO^–₃
II. H₃O⁺
III. HSO₄
IV. HSO₃F
Which one of the following is the correct sequence of their acid strength ?
(a) IV < II < III < I
(b) II < III < I < IV
(c) I < III < II < IV
(d) III < I < IV < II     

Question. Three reactions involving H₂PO^–₄ are given below
I. H₃PO₄ + H₂O → H₃O⁺ + H₂PO^–₄ 
II. H₂PO^–₄ + H₂O → HPO^2-₄+ H₃O⁺
III. H₂PO^–₄  + OH^– → H₃PO₄ + O^2-
In which of the above does H₂PO^–₄ act as an acid?
(a) Only II
(b) Both I and II 
(c) Only III
(d) Only I     

Question. Which of the following behaves as Lewis acid and not as Bronsted acid? 
(a) HCl
(b) H₂SO₄
(c) HSO₃
(d) SO₃       

Question. Which one of the following is the weakest acid?
(a) HF
(b) HCl 
(c) HBr
(d) HI   

Question. Which of the following acid is stronger than benzoic acid (K_a = 6.3 X 10^-5)? 
(a) A (K_a = 1.67 x 10^-8)
(b) B (pK_a = 6.0)
(c) C (pK_a = 4.0)
(d) D (K_a = 1.0 x 10^-5) 

Question. For a diprotic acid, which of the following is true for 1st and 2nd ionisation constants (Ka₁ and Ka₂) ? 
(a) K_a1 = Ka₂
(b) K_a1 > Ka₂
(c) Ka₂ > K_a1
(d) Ka₂ ≥ K_a1  

Question. Water is well known amphoprotic solvent. In which chemical reaction, water is behaving as a base ? 
(a) H₂SO₄ + H₂O → H₃O⁺ + HSO^–₄
(b) H₂O + H₂O → H₃O⁺ + OH^–
(c) H₂O + NH₂ → NH₃ + OH^–
(d) H₂O + NH₃ → NH⁺₄+ OH^–     

Question. Which one of the following species acts as both Bronsted acid and base ? 
(a) H₂PO^–₂
(b) HPO^2-₃
(c) HPO^2-₄
(d) All of these   

Question. Which of the following is a Lewis acid ? 
(a) Cl^–
(b) H₃O⁺
(c) PF₃
(d) C₂H₅OH       

Question. For a concentrated solution ofa weak electrolyte A_xB_Y of concentration C, the degree of dissociation ‘a.’ is given as
(a) a = √K_eq /C(x+ y)
(b) a = √K_eq /C(xy)
(c) a = (K_eq /C^x+y-1 x^X y^Y)^{1/(x + y)}
(d) a = (K_eq /Cxy)       

Question. Conjugate acid of HF^–₂ is
(a) H+
(b) HF
(c) F^–₂
(d) H₂F₂     

Question. Some chemists at ISRO wished to prepare a saturated solution of a silver compound and they wanted it to have the highest concentration of silver ion possible. Which of the following compounds, would they use?
      K_sp(AgCl) = 1.8 x 10^-10
      K_sp(AgBr) = 5.0 x 10^-13
      Ks_p(Ag₂CrO₄) = 2.4 x 10^-12
(a) AgCl
(b) AgBr
(c) Ag₂CrO₄
(d) None of these     

Question. Solubility of Al(OH)₃ = s,K_sp will be 
(a) 108S³
(b) 27S³
(c) 4S⁴
(d) 27S⁴   

Question. Amines behave as     
(a) Lewis acid
(b) Lewis base
(c) aprotic acid
(d) neutral compound   

Question. Which of the following is not a conjugate acid-base pair? 
(a) HPO^3-₃, PO^3-₃
(b) H₂PO^–₄, HPO^2-₄
(c) H₃PO₄ , H₂PO₄
(d) H₂PO^–₄, PO^3-₃       

Question. According to Bronsted and Lowry , the strength of an acid depends upon 
(a) the tendency to gain electrons
(b) the tendency to loss protons
(c) the tendency to accept protons
(d) the tendency to loss electrons     

Question. Which is a Lewis base?
(a) B₂H₆
(b) LiAIH₄
(c) AIH₃
(d) NH₃     

Question. The solubility of Agl in Nal solution is less than that in pure water because 
(a) the temperature of the solution decreases
(b) solubility product of AgI is less than that ofNal
(c) of common ion effect
(d) Agl forms complex with Nal     

Question. The solubility product of a sparingly soluble salt AX ₂ is 3.2 x 10^-11 . Its solubility (in mol/L) is 
(a) 5.6 X 10^-6
(b) 3.1 X 10^-4
(c) 2 X 10^-4
(d) 4 X 10^-4     

Question. If solubility of calcium hydroxide is ✓3, then its solubility product will be 
(a) 27
(b) 3
(c) 9     
(d) 12✓3     

Question. The solubility product of BaCl₂ is 4 x 10^-9 . Its solubility (in mol/L) is
(a) 4 x 10^-3
(b) 4 x 10^-9
(c) 1 x 10^-3
(d) 1 x 10^-9     

Question. The molar solubility (in mo! L_-1) of a sparingly soluble salt MX ₄ is ‘s’. The corresponding solubility product is K ,_sp. Sis given in terms of K_sp by the relation
(a) S = (K_sp 1/ 28)^1/4
(b) S = (128 K_sp )^1/4
(c) S = (256 K_sp )^1/5
(d) S = (K_sp / 256)^1/5     

Question. The value of the ionic product of water depends 
(a) on volume of water
(b) on temperature
(c) changes by adding acid or alkali
(d) always remain constant     

Question. When ammonium chloride is added to ammonia solution, the pH of the resulting solution will be
(a) increased
(b) seven
(c) decreased
(d) unchanged    

Question. The solubility in water of a sparingly soluble salt AB₂ is 1.0 x 10^-5 mol L^-1 . Its solubility product number will be
(a) 4 x 10^-15 
(b) 4 X 10^-10
(c) 1 X 10^-15
(d) 1 X 10^-10     

Question. The K_sp of Ca₃(PO₄)₂ his
(a) [Ca²⁺] [PO^3-₄]²
(b) [Ca²⁺]³ [PO^3-₄]
(c) [Ca²⁺] [PO^3-₄]
(d) [Ca²⁺]³ [PO^3-₄]²       

Question. The solubility of CaF₂ is pure water is 2.3 x 10^-6 mol dm^-3. Its solubility product will be 
(a) 4.8 x 10^-18
(b) 48.66 x 10^-18
(c) 4.9 x 10^-11
(d) 48.66 x 10^-15     

Question. At 90°C, pure water has H₃O⁺ ion concentration of 10^-6 mol / L^-1 . The K_w at 90°C is 
(a) 10^-6
(b) 10^-14
(c) 10^-12
(d) 10^-8     

Question. A precipitate of AgCI is formed when equal volumes of the following are mixed.
[ K _sp for AgCI = 10^-10] 
(a) 10^-4 M AgNO₃ and 10^-7 M HCI
(b) 10^-5 MAgNO₃ and 10^-6 MHCI
(c) 10^-5 M AgNO₃ and 10^-4 M HCI
(d) 10^-6 M AgNO₃ and 10^-6 M HCI     

Question. The correct expression for the solubility product of Ca₃ (PO₄)₂ is 
(a) 108s⁵     
(b) 27s⁵
(c) 16s⁴
(d) 81s⁴       

Question. The solubility product of a salt having general formula MX ₂ , in water is 4 x 10^-2 . The concentration of M²⁺ ions in the aqueous solution of the salt is 
(a) 4.0 x 10^-10 M
(b) 1.6 x 10^-4 M
(c) 1.0 x l0^-4 M
(d) 2.0 x 10^-3       

Question. On adding 0.1 M solution each of [Ag⁺], [Ba²⁺],[Ca²⁺] in a Na₂SO₄ solution, species first precipitated is (K_sp BaSO₄ = 10^-11 ,K_sp CaSO₄ = 10^-6, K_sp AgSO₄ =10^-5)
(a) Ag₂SO₄
(b) BaSO₄
(c) CaSO₄
(d) All of the above   

Question. The solubility of Pb(OH)₂ in water is 6.7 x 10-⁶M. Its solubility in a buffer solution of pH = 8 would be
(a) 1.2 x 10^-2
(b) 1.6 x 10^-3 
(c) 1.6 x 10^-2
(d) 1.2 x 10^-3     

Question. For which of the following sparingly soluble salt, the solubility (s)and solubility product (K_sp)are related by the expressions= (K_sp / 4 )^1/3 ? 
(a) BaSO₄
(b) Ca₃ (PO₄)₂
(c) Hg₂Cl₂
(d) Ag₃PO₄     

Question. The solubility of Sb₂S₃ in water is 1.0 x 10^-5 mol / L at 298 K. What will be its solubility product ?
(a) 108 x 10^-25
(b)1.0 x 10^-25
(c) 144 x 10^-25
(d) 126 x 10^-24   

Question. The first and second dissociation constants of an acid H₂A are 1.0 x 10^-5 and 5. 0 x 10^-10 , respectively. The overall dissociation constant of the acid will be 
(a) 5.0 x 10^-5
(b) 5.0 x 10¹⁵
(c) 5.0 x 10^-15
(d) 0.2 x 10⁵       

Question. Conjugate base of H₂PO^–₄ is 
(a) H₃PO₄
(b) P₂O₅
(c) PO^3-₄
(d) HPO^2-₄       

Question. If for N₂ + 3H₂ ⇌ 2NH₃ ,K_eq = 1.6x 10^-5 ,thenthe value of K_eq for the reaction NH₃ ⇌ 1/2N₂ + 3/2 H₂will be
(a) 6.25
(b) 25
(c) 250
(d) 500     

Question. 3 moles of A and 4 moles of B are mixed together and allowed to come into equilibrium according to the following reaction.
3A (g) + 4B (g) ⇌ 2C (g) + 3D (g)
When equilibrium is reached, there is I mole of C. The equilibrium extent of the reaction is 
(a) 1/ 4
(b) 1/3
(c) 1/2   

Question. For the following three reactions I, II and m, equilibrium constants are given
I. CO (g) + H₂O(g) ⇌ CO₂(g)+ H₂(g),K₁
II CH₄(g)+ H₂O(g) ⇌ CO(g) + 3H₂(g),K₂
III. CH₄(g)+ 2H₂O(g) ⇌ CO₂(g) + 4H₂(g),K₃
Which of the following relations is correct? 
(a) K₁ √K₂ =  K₃
(b) K₂  K₃ = K₁
(c) K₃ = K₁ K₂
(d) K₃ K³₂ = K₁²     

Question. The equilibrium constants K_Pi and K_Pi for the reactions X ⇌ 2Y and Z ⇌ P + Q, respectively are in the ratio of 1 : 9. If the degree of dissociation of X and Z be equal, then the ratio of total pressure at these equilibria is 
(a) 1 : 36
(b) 1 : 1
(c) 1 : 3
(d) 1 : 9     

Question. In a 500 mL flask, the degree of dissociation of PCl₅ at equilibrium is 40% and the initial amount is 5 moles. The value of equilibrium constant (in mol L^-1 ) for the decomposition of PCl₅ is 
(a) 2.33
(b) 2.66
(c) 5.32
(d) 4.66       

Question. Formaldehyde polymerises to fom1 glucose according to the reaction, 6HCHO ⇌ C₆H₁₂O₆ .
The theoretically computed equilibrium constant for this reaction is found to be 6 x 10²² . If I M solution of glucose dissociates according to the above equilibrium, the concentration of formaldehyde in the solution will be
(a) 1.6x 10^-2 M
(b) 1.6x 10^-4 M 
(c) 1.6 x 10^-6 M
(d) 1.6 x 10^-8 M     

Question. 1n chemical equilibrium, the value of Δn (number of molecules of products – number of molecules of reactants), is negative, then the relationship between K_P and K_c will be 
(a) K_p – Kc = 0
(b) K_p = Kc(RT)^+Δmg
(c) K_p = Kc(RT)^-Δm
(d) K_p = KC       

Question. Three moles of PCl₅ , three moles of PCl₃ and two moles of Cl₂ are taken in a closed vessel. If at equilibrium, the vessel has 1.5 moles of PCl₅ , the number of moles of PCl₃ present in it is 
(a) 5
(b) 3
(c) 6
(d) 4.5       

Question. 2Hl (g) ⇌ H₂ (g) + l₂ (g) – QkJ
For the above reaction, equilibrium constant depends upon
(a) temperature
(b) pressure
(c) catalyst
(d) volume     

Question. 1.6 moles of PCl₅ (g) is placed in 4 dm³ closed vessel. When the temperature is raised to 500 K, it decomposes and at equilibrium, 1.2 moles of PCl₅ (g) remains. What is the K_c value for the decomposition of PCl₅ (g) into PCl₃ (g) and Cl₂ (g) at 500 K ? 
(a) 0.013
(b) 0.050
(c) 0.033
(d) 0.067   

Question. CO (g) + 1/2 O₂ (g ) → CO₂ (g) For the above reaction in gaseous phase, the value of K_P / K_c is
(a) (RT)^1/2
(b) (RT)^-1/2 
(c) (RT)
(d) (RT)^-1       

Question. In the reaction, H₂( g) + Cl₂(g) ⇌ 2HCl (g ),
(a) K_p ≠ K_c
(b) K_p = K_c
(c) K_p > K_c
(d) K_p < K_c     

Question. 1 mole of H₂ and 2 moles of I₂ are taken initially in a 2 L vessel. The number of moles of H₂ at equilibrium is 0.2. Then, the number of moles of I₂ and HI at equilibrium respectively are 
(a) 1.2, 1.6
(b) 1.8, 1.0
(c) 0.4, 2.4
(d) 0.8, 2.0     

Questionuestion. Ammonium carbonate decomposes as
      NH₂COONH₄(s) ⇌ 2 NH₃ (g) + CO₂ (g)
For the reaction, K_P = 2.9 x 10^-5 atm³ . If we start with 1 mole of the compound, the total pressure at equilibrium would be 
(a) 0.766 atm
(b) 0.0581 atm
(c) 0.0388 atm
(d) 0.0194 atm     

Question. The equilibrium constant (K_P) for the decomposition of gaseous H₂O as
H₂O(g) ⇌ H     2 (g) + 1/2 O₂ (g)
is related to degree of dissociation (a) at a total pressure p is given by 
(a) K_p = a³ p^1/2/(1 + α) (2 + α)^1/2
(b) K_p = a³ p^3/2/(1 – α) (2+α)^1/2
(c) K_p = a^3/2 p²/(1 – α) (2 + α)^1/2
(d) K_p = a³ p^1/2/(1 – α) (2+ α)^1/2       

Question. On doubling p and V with constant temperature, the equilibrium constant will 
(a) remain constant
(b) become double
(c) become one-fourth
(d) None of the above       

Question. At 600° C,K _P for the following reaction is 1 atm.
          X(g) ⇌ Y(g)+ Z(g)
At equilibrium, 50% of X ( g) is dissociated. The total pressure of the equilibrium system is p atm. What is the partial pressure (in atm) of X (g) at equilibtium? 
(a) 1
(b) 4
(c) 2
(d) 0.5     

Question. Which one of the following substances has the highest proton affinity ? 
(a) H₂O
(b) H₂S
(c) NH₃
(d) PH₃       

Question. Which is a Lewis base?
(a) B₂H₆
(b) LiAIH₄
(c) AIH₃
(d) NH₃     

Question. In Lowry-Bronsted concept, H⁺ donor is known as
(a) acid
(b) base 
(c) Both (a) and (b)
(d) None of these   

Question. An example of a Lewis acid is 
(a) MgCI₂
(b) SnCI₄
(c) AICI₃
(d) NaCI     

Question. Which of the following is a Lewis base ? 
(a) NaOH
(b) NH₃
(c) BCI₃
(d) All of these        

Question. The ionisation of strong compared to water, is
(a) weak, low
(b) strong, more
(c) medium, the same electrolytes in acetic acid,
(d) no ionisation, 100%     

Question. An acid solution of 0.005 M has a pH of 5. The degree of ionisation of acid is 
(a) 0.1 x 10^-2
(b) 0.2 x 10^-2
(c) 0.5 x 10^-4
(d) 0.6 x 10^-6       

Question. Strongest conjugate base is
(a) CIO^–
(b) ClO^–₂
(c) ClO^–₃
(d) ClO^–₄     

Question. What kind of molecule AICI₃ is?
(a) Bronsted acid 
(b) Lewis acid
(c) Lewis base
(d) Bronsted base       

Question. Which of the following is a Lewis acid?
(a) AICI₃
(b) Cl^–
(c) CO
(d) C₂H₂       

Question. Ammge NH⁺₄ , H₂O, H₃O⁺, HF and Off in increasing order of acidic nature 
(a) H₃O⁺ < NH⁺₄ < HF < OH^– < H₂O
(b) NH⁺₄! < HF < H₃O⁺ < H₂O < OH^–
(c) OH^– < H₂O < NH⁺₄ < HF < H₃O⁺
(d) H₃O⁺> HF > H₂O > NH⁺₄> OH^–     

Question. Which one of the following is not an amphoteric substance ?
(a) HNO₃
(b) HCO^–₃
(c) H₂O
(d) NH₃     

Question. Conjugate acid of S2O^-2₈ is
(a) H₂S₂O₈
(b) H₂SO₄
(c) HS₂O^–₈
(d) HSO^–₄     

Question. CH₃COOH is weaker acid than H₂SO₄ . It is due to
(a) more ionisation
(b) less ionisation 
(c) covalent bond
(d) electrovalent bond       

Question. What is the conjugate base of OH^– ? 
(a) O^2-
(b) O^–
(c) H₂O
(d) O₂       

Question. The values of dissociation constant of bases are given below. Which is the weakest base? 
(a) 1.8 X 10^-5
(b) 4.8 X 10^-10
(c) 7.2 X 10^-11
(d) 7.07 x 10^-7         

Question. The species among the following, which can act as an acid and a base is 
(a) HSO^–₄
(b) SO^2-₄
(c) H₃O⁺
(d) Cl^–               

Question. The pH of a neutral water sample is 6. 5. Then, the temperature of water
(a) is 25°C
(b) is more than 25°C
( c) is less than 25°C
(d) can be more or less than 25°C     

Question. On mixing equal volumes of two buffer solutions of pH value 3 and 5, the pH of the resultant solution will be
(a) 3.3
(b) 4.0 
(c) 4.7
(d) 5.3       

Question . Which of the following is not a Lewis acid ? 
(a) BF₃
(b) AICI₃
(c) SO₂
(d) H₂O       

Question . Which is a Lewis base?
           I₂ + I^– → I^–₃
(a) I₂
(b) I^–₃
(b) I^–
(d) None of these     

Question . The conjugate acid of NH^–₂ is 
(a) N₂H₄
(b) NH⁺₄
(c) NH₂OH      
(d) NH₃     

Question . Ostwald’s dilution law is applicable for
(a) weak electrolyte
(b) strong electrolyte
(c) both weak and strong electrolyte
(d) non-electrolyte      

Question . Metal ions like Ag⁺, Cu²⁺ etc., act as
(a) Bronsted acids
(b) Bronsted bases
(c) Lewis acids
(d) Lewis bases       

Question . If 200 mL of a 0.031 molar solution of H₂SO₄ are added to 84 mL of a 0.150 M KOH solution, what is the value of pH of the resulting solution? 
(a) 12.4
(b) 1.7
(c) 2.2
(d) 10.9