Please refer to Assignments Class 11 Chemistry Equilibrium Chapter 7 with solved questions and answers. We have provided Class 11 Chemistry Assignments for all chapters on our website. These problems and solutions for Chapter 7 Equilibrium Class 11 Chemistry have been prepared as per the latest syllabus and books issued for the current academic year. Learn these solved important questions to get more marks in your class tests and examinations.
Equilibrium Assignments Class 11 Chemistry
Question. A certain buffer solution contains equal concentration of X– and HX. The ka for HX is 10-8. The pH of the buffer is
(a) 3
(b) 8
(c) 11
(d) 14
Answer
B
Question. The solubility product of CuS, Ag2S and HgS are 10-31, 10-44 and 10-54 respectively. The solubilities of these sulphides are in the order
(a) HgS > Ag2S > CuS
(b) CuS > Ag2S > HgS
(c) Ag2S > CuS > HgS
(d) AgS > HgS > CuS
Answer
C
Question. If, in the reaction N2O4 2NO2, x is that part of N2O4 which dissociates, then the number of molecules at equilibrium will be
(a) 1
(b) 3
(c) (1 + x)
(d) (1 + xy)²
Answer
A
Question. Oxidation number of Iodine varies from
(a) -1 to +1
(b) -1 to +7
(c) +3 to +5
(d) -1 to +5
Answer
B
Question. Which of the following statements is correct about the equilibrium constant?
(a) Its value increases by increase in temperature
(b) Its value decreases by decrease in temperature
(c) Its value may increase or decrease with increase in temperature
(d) Its value is constant at all temperatures
Answer
C
Question. Calculate the pOH of a solution at 25°C that contains 1 × 10-10 M of hydronium ions, i.e. H3O+.
(a) 4.000
(b) 9.000
(c) 1.000
(d) 7.000
Answer
A
Question. [ OH–] in a solution is 1 mol L–. The pH the solution is
(a) 1
(b) 0
(c) 14
(d) 10-14
Answer
C
Question. The position of some metals in the electrochemical series in decreasing electropositive character isMg > Al > Zn > Cu > Ag. In a chemical factory, a worker by accident used a copper rod to stir a solution of aluminium nitrate; he was scared that now there would be some reaction in the solution, so he hurriedly removed the rod from the solution and observed that
(a) The rod was coated with Al
(b) An alloy of Cu and Al was being formed.
(c) The solution turned blue in colour
(d) There was no reaction.
Answer
D
Question. The solubility product of a salt having general formula MX2. In water is : 4 × 10-12. The concentration of M2+ ions in the aqueous solution of the salt is
(a) 4.0 × 10-10 M
(b) 1.6 × 10-4 M
(c) 1.0 × 10-4 M
(d) 2.0 × 10-6 M
Answer
C
Question. Among the following the weakest Bronsted base is
(a) F–
(b) Cl–
(c) Br–
(d) I–
Answer
D
Question. For the reaction 2SO2(g) + O2(g) ⇌ 2SO3(g) at 300 K, the value of ΔG° is –690.9 R. The equilibrium constant value for the reaction at that temperature is (R is gas constant)
(a) 10 atm–1
(b) 10 atm
(c) 10
(d) 1
Answer
A
Question. Calculate Kc for the reversible process given below if Kp = 167 and T = 800°C.
CaCO3(s) ⇌ CaO(s) + CO2(g)
(a) 1.95
(b) 1.85
(c) 1.89
(d) 1.60
Answer
C
Question. The equilibrium constant, Kp for the reaction,
PCl5 ⇌ PCl3 + Cl2 is 1.6 at 200°C .
The pressure at which PCl5 will be 50% dissociated at 200°C is
(a) 3.2 atm
(b) 4.8 atm
(c) 2.4 atm
(d) 6.4 atm
Answer
B
Question. If the pH increases from 5 to 7, then acidic strength decreases _________ times.
(a) 2
(b) 20
(c) 10
(d) 100
Answer
D
Question. In HS–, I–, R — NH2, NH3 order of proton accepting tendency will be
(a) I– > NH3 > R — NH2 > HS–
(b) NH3> R — NH2 > HS– > I–
(c) R — NH2 > NH3 > HS– > I–
(d) HS– > R — NH2 > NH3 > I–
Answer
C
Question. In Bronsted–Lowry concept of acid-base, H+ donor is a/an
(a) acid
(b) basic
(c) exclusively amphoteric substance
(d) hydroxide acceptor.
Answer
A
Question. In the reaction;
Fe(OH)3(s) ⇌ Fe3+(aq) + 3OH–(aq), if the concentration of OH– ions is decreased by 1/4 times, then the equilibrium concentration of Fe3+ will increase by
(a) 8 times
(b) 16 times
(c) 64 times
(d) 4 times.
Answer
C
Question. What will be the solubility product of AX3?
(a) 27S4
(b) 4S3
(c) 36S4
(d) 9S3
Answer
A
Question. In which of the following equilibrium Kc and Kp are not equal?
(a) 2NO(g) ⇌ N2(g) + O2(g)
(b) SO2(g) + NO2(g) ⇌ SO3(g) + NO(g)
(c) H2(g) + I2(g) ⇌ 2HI(g)
(d) 2C(s) + O2(g) ⇌ 2CO2(g)
Answer
D
Question. The solubility of Ca3(PO4)2 in water is y moles/litre. Its solubility product is
(a) 6y4
(b) 36y4
(c) 64y5
(d) 108y5
Answer
D
Question. Using the Gibbs’ energy change, ΔG° = +63.3 kJ, for the following reaction,
Ag2CO3(s) 2Ag+(aq) + CO2–3(aq)
the Ksp of Ag2CO3(s) in water at 25°C is
(R = 8.314 J K–1 mol–1)
(a) 3.2 × 10–26
(b) 8.0 × 10–12
(c) 2.9 × 10–3
(d) 7.9 × 10–2
Answer
B
Question. 4 moles of A are mixed with 4 moles of B, when 2 moles of C and D are formed at equilibrium according to the reaction,
A + B ⇌ C + D
the value of equilibrium constant is
(a) 4
(b) 1
(c) 1/2
(d) 1/4
Answer
B
Question. Identify a species which is ‘NOT’ a Bronsted acid but a Lewis acid.
(a) BF3
(b) H3O+
(c) NH3
(d) HCl
Answer
A
Question. Consider the general hypothetical reaction,
A(s) 2B(g) + 3C(g)
If the concentration of C at equilibrium is doubled, then after the equilibrium is re-established, the concentration of B will be
(a) two times the original value
(b) one half of its original value
(c) 1/ 2√2 times the original value
(d) 2√2times the original value.
Answer
C
Question. Among the following, the one which can act as both Bronsted acid as well as Bronsted base is
(a) H3PO4
(b) AlCl3
(c) CH3COO–
(d) H2O
Answer
D
Question. The pH of 10–4 M KOH solution will be
(a) 4
(b) 11
(c) 10.5
(d) 10
Answer
D
Question. Which of these is least likely to act as a Lewis base?
(a) BF3
(b) PF3
(c) CO
(d) F–
Answer
A
Question. Buffer solutions have constant acidity and alkalinity because
(a) these give unionised acid or base on reaction with added acid or alkali
(b) acids and alkalies in these solutions are shielded from attack by other ions
(c) they have large excess of H+ or OH– ions
(d) they have fixed value of pH.
Answer
A
Question. Of the following the incorrect relation is
(a) ΔG = ΔG° + RTlnK
(b) ΔG° = –RTlnK
(c) ΔG° = ΔG + RTlnK
(d) K = e–Δ G°/RT
Answer
C
Question. The reaction quotient, Qc is useful in predicting the direction of the reaction. Which of the following is incorrect?
(a) If Qc > Kc, net reaction goes from right to left.
(b) If Qc < Kc, net reaction goes from left to right.
(c) If Qc = Kc, no net reaction occurs.
(d) If Qc > Kc, net reaction goes from left to right.
Answer
D
Assertion & Reason Based MCQs :
A statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
(c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.
Question. Assertion : For any chemical reaction at a particular temperature, the equilibrium constant is fixed and is a characteristic property.
Reason : Equilibrium constant is independent of temperature.
Answer
C
Question. Assertion : Kp can be equal to, less than or greater than the value of Kc.
Reason : Kp = Kc(RT)Δn where Δn is the change in the number of moles of gaseous reactants and products.
Answer
A
Question. Assertion : H3PO4 is a stronger acid than H2PO–4
Reason : pKa1 is greater than pKa2 for H3PO4.
Answer
C
Question. Assertion : At 25°C the pH of 10–7 M HCl is 6.69.
Reason : pH of acidic solution is always below 7 at 25°C.
Answer
A
Question. Assertion : The active mass of pure solid is taken unity.
Reason : The active mass of pure solids depends on density and molecular mass. The density and molecular mass of pure solids are constant.
Answer
A
Question. Assertion : For the equilibrium mixture CO(g) + 3H2(g) CH4(g) + H2O(g) if the volume is decreased, reaction proceeds in the forward direction.
Reason : For the methanation reaction (above), decrease in volume causes Qc > Kc.
Answer
C
Question. Assertion : On dilution, the solubility of BaSO4 increases.
Reason : On dilution, Ksp increases.
Answer
C
Question. Assertion : The value of Kw at 25°C is 1.0 × 10–14 mol2 dm–6.
Reason : Kw of water changes with change in temperature.
Answer
B
Question. Assertion : At constant temperature, the pressure of the gas is proportional to its concentration.
Reason : Kp = Kc for all reactions.
Answer
C
Question. Assertion : The equilibrium constant does not change on addition of catalyst.
Reason : A catalyst provides an alternative path of lower activation energy for conversion of reactants to products.
Answer
B
