JEE Chemistry Equilibrium MCQs Set C

Question: Which of the following statements about pH and H⁺ ion concentration is incorrect?

• a) A solution of the mixture of one equivalent of each of CH₃COOH and NaOH has a pH of 7
• b) pH of pure neutral water is not zero
• c) Addition of one drop of concentrated HCl in NH₄OH solution decreases pH of the solution
• d) None of these

Answer: A solution of the mixture of one equivalent of each of CH₃COOH and NaOH has a pH of 7

Question: H₂S gas when passed through a solution of cations containing HCl precipitates the cations of second group of qualitative analysis but not those belonging to the fourth group. It is because

• a) presence of HCl decreases the sulphide ion concentration
• b) solubility product of group II sulphides is more than that of group IV sulphides
• c) presence of HCl increases the sulphide ion concentration
• d) sulphides of group IV cations are unstable in HCl

Answer: presence of HCl decreases the sulphide ion concentration

Question: A salt ‘X’ is dissolved in water of pH = 7. The salt is made resulting solution becomes alkaline in nature. The salt is made

• a) A weak acid and strong base
• b) A weak acid and weak base
• c) A strong acid and weak base
• d) A strong acid and strong base

Answer: A weak acid and strong base

Question: Aqueous solution of ferric chloride is acidic due to

• a) hydrolysis
• b) polarization
• c) ionization
• d) dissociation

Answer: hydrolysis

Question: The pK_a of a weak acid (HA) is 4.5. The pOH of an aqueous buffer solution of HA in which 50% of the acid is ionized is

• a) 9.5
• b) 4.5
• c) 7.0
• d) 2.5

Answer:  9.5

Question:

• a) 9.43
• b) 8.73
• c) 9.08
• d) 11.72

Answer: 9.43

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Which of the following pairs constitutes a buffer?

• a) HNO₂ and NaNO₂
• b) HNO₃ and NH₄NO₃
• c) NaOH and NaCl
• d) HCl and KCl

Answer: HNO₂ and NaNO₂

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: these give unionised acid or base on reaction with added acid or alkali

Question: The buffering action of an acidic buffer is maximum when its pH is equal

• a) pK_a
• b) 7
• c) 5
• d) 1

Answer:  pK_a

Question:  When a buffer solution, sodium acetate and acetic acid is diluted with water

• a) H⁺ ion concentration remains unaltered
• b) OH^– ion conc. increases
• c) H⁺ ion concentration increases
• d) Acetate ion concentration increases

Answer: H⁺ ion concentration remains unaltered

Question: The product of ionic concentration in a saturated solution of an electrolyte at a given temperature is constant and is known as

• a) Solubility product
• b) Ionic product of the electrolyte
• c) Ionization constant
• d) Dissociation constant

Answer: Solubility product

Question:  The K_sp for Cr(OH)₃ is 1.6 × 10_–30. The solubility of this compound in water is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: At 25°C, the solubility product of Mg(OH)₂ is 1.0 × 10^–11. At which pH, will Mg²⁺ ions start precipitating in the form of Mg(OH)₂ from a solution of 0.001 M Mg²⁺ ions?

• a) 10
• b) 8
• c) 9
• d) 11

Answer: 10

Question: pH of a saturated solution of Ba(OH)₂ is 12. The value of solubility product (K_sp) of Ba(OH)₂ is

• a) 5.0 × 10^–7
• b) 5.0 × 10^–6
• c) 3.3 × 10^{– 7}
• d) 4.0 × 10^–6

Answer:  5.0 × 10^–7

Question: If s and S are respectively solubility and solubility product of a sparingly soluble binary electrolyte then

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) Solubility product of As₂S₃ is less than that of ZnS
• b) Enough As⁺³ are present in acidic medium
• c) Zinc salt does not ionise in acidic medium
• d) Solubility product changes in presence of an acid

Answer: Solubility product of As₂S₃ is less than that of ZnS

Question:

• a) 5.1 × 10^–5 M
• b) 4.1 × 10^–5 M
• c) 7.1 × 10^–8 M
• d) 8.1 × 1^–7 M

Answer: 5.1 × 10^–5 M

Question: Solubility product of silver bromide is 5.0 × 10^–13. The quantity of potassium bromide (molar mass taken as 120 g mol^–1) to be added to 1 litre of 0.05 M solution of silver nitrate to start the precipitation of AgBr is

• a) 1.2 × 10^–9 g
• b) 5.0 × 10^–8 g
• c) 1.2 × 10^–10 g
• d) 6.2 × 10^–5 g

Answer:  1.2 × 10^–9 g 

Question:

• a) 10
• b) 8
• c) 9
• d) 11

Answer: 10

Question:  Read the following statements carefully and choose the correct answer

(i) Water and water vapour remain in equilibrium position at atmospheric pressure (1.013 bar) and at 100°C in a closed vessel.
(ii) The boiling point of water is 100°C at 1.013 bar pressure
(iii) Boiling point of the liquid depends on the atmospheric pressure.
(iv) Boiling point depends on the altitude of the place; at high altitude the boiling point increases

• a) (i), (ii) and (iii) are correct
• b) only (iii) is correct
• c) (i), (iii) and (iv)
• d) (i), (ii) and (iv) are correct

Answer: (i), (ii) and (iii) are correct

Question:

• a) (i), (ii) and (iv) are correct
• b) (i) , (iii) and (iv)
• c) (i), (ii) and (iii) are correct
• d) only (iii) is correct

Answer: (i), (ii) and (iv) are correct

Question:  Identify the CORRECT statements below regarding chemical equilibrium:

(i) All chemical reactions which are in equilibrium are irreversible.
(ii) Equilibrium is achieved when the forward reaction rate equals the reverse reaction rate.
(iii) Equilibrium is achieved when the concentrations of reactants and product remain constant.
(iv) Equilibrium is dynamic in nature

• a) (i), (ii), (iii) and (iv) are correct
• b) (i), (ii) and (iii) are correct
• c) only (ii) is correct
• d) (i), (ii) and (iv) are correct

Answer: (i), (ii), (iii) and (iv) are correct

Question: Read the following statements and choose the correct option.

(i) The value of equilibrium constant is independent of initial concentrations of the reactants and products.
(ii) Equilibrium constant is temperature dependent
(iii) The equilibrium constant for the reverse reaction is equal to the inverse of the equilibrium constant for the forward reaction.
(iv) The equilibrium constant for the reverse reaction is equal to the equilibrium constant for the forward reaction.

• a) (i), (ii) and (iii) are correct
• b) only (iii) is correct
• c) (i), (iii) and (iv)
• d) (i), (ii) and (iv) are correct

Answer: (i), (ii) and (iii) are correct

Question:

• a) (i) , (iii) and (iv)
• b) (i), (ii) and (iii) are correct
• c) only (iii) is correct
• d) (i), (ii) and (iv) are correct

Answer: (i) , (iii) and (iv)

Question:

• a) (i), (ii) and (iii) are correct
• b) (i) and (ii)
• c) (ii) and (iii) are correct
• d) only (iii) is correct

Answer: (i), (ii) and (iii) are correct

Question:  Read the following statements and choose the correct option

(i) Most of the acids taste sour
(ii) Acids turns blue litmus paper into red
(iii) Bases turns red litmus paper blue
(iv) Bases taste bitter and feel soapy

• a) All statements are correct
• b) (i), (ii) and (iii) are correct
• c) (i), (iii) and (iv)
• d) (i), (ii) and (iv) are correct

Answer: All statements are correct

Question: Which of the following statements are correct ?

(i) Strong acids have very weak conjugate bases
(ii) Weak acids have very strong conjugate bases
(iii) Strong bases have strong conjugate acids
(iv) Weak bases have weak conjugate acids

• a) (i) and (ii)
• b) (ii) and (iv)
• c) (i) and (iii)
• d) (iii) and (iv)

Answer: (i) and (ii)

Question: Which of the following statement(s) is/are correct ?

(i) Water has ability to act both as an acid and a base
(ii) In pure water one H₂O molecule donate proton and acts an acid and another water molecule accepts a proton and acts as a base.

• a) Both (i) and (ii)
• b) Only (i)
• c) Neither (i) nor (ii)
• d) Only (ii)

Answer: Both (i) and (ii)

Question:

• a) (i), (ii) and (iv)
• b) (ii) and (iii)
• c) (i) and (iv)
• d) (i) and (iv)

Answer: (i), (ii) and (iv)

Question:  Read the following statements and choose the correct option

(i) K_a (ionization constant) is a measure of the strength of the acids
(ii) Smaller the value of K_a, the stronger is the acid
(iii) K_a is a dimensionless quantity

• a) Statements (i) and (iii) are correct
• b) Statements (i), (ii) and (iii) are correct
• c) Statements (ii) and (iii) are correct
• d) Statements (i) and (ii) are correct

Answer: Statements (i) and (iii) are correct

Question:

• a) Both (i) and (ii)
• b) Only (i)
• c) Neither (i) nor (ii)
• d) Only (ii)

Answer: Both (i) and (ii)

Question: Which of the following statements are correct ?

(i) The extent of dissociation of an acid depends on the strength and polarity of the H –– A bond (where A is an electronegative element.)
(ii) As the strength of H–A bond increases, the energy required to break the bond decreases.
(iii) As the electronegativity difference between the atoms H and A increases, acidity increases

• a) (i) and (iii)
• b) (i) and (ii)
• c) (ii) and (iii)
• d) (i), (ii) and (iii)

Answer:  (i) and (iii)

Question:

• a) A – (q), B – (r), C – (p)
• b) A – (p), B – (r), C – (q)
• c) A – (r), B – (q), C – (p)
• d) A – (p), B – (q), C – (r)

Answer: A – (q), B – (r), C – (p)

Question:

• a) A – (q) ; B – (s) ; C – (r) ; D – (p)
• b) A – (s) ; B – (q) ; C – (p) ; D – (r)
• c) A – (r) ; B – (s) ; C – (q) ; D – (p)
• d) A – (p) ; B – (r) ; C – (q) ; D – (s)

Answer: A – (q) ; B – (s) ; C – (r) ; D – (p)

Question:

• a) A – (q), B – (r), C – (p)
• b) A – (r), B – (q), C – (p)
• c) A – (p), B – (r), C – (q)
• d) A – (q), B – (p), C – (r)

Answer:  A – (q), B – (r), C – (p)

Question:

• a) A – (q), B – (p), C – (s), D – (r)
• b) A – (p), B – (q), C – (r), D – (s)
• c) A – (r), B – (p), C – (s), D – (q)
• d) A – (s), B – (q), C – (p), D – (r)

Answer: A – (q), B – (p), C – (s), D – (r)

Question:

• a) A – (r), B – (s), C – (q), D – (p)
• b) A – (s), B – (p), C – (q), D – (r)
• c) A – (q), B – (s), C – (r), D – (p)
• d) A – (p), B – (q), C – (r), D – (s)

Answer: A – (r), B – (s), C – (q), D – (p)

Question:

• a) A – (q), B – (p), C – (r)
• b) A – (p), B – (r), C – (q)
• c) A – (r), B – (q), C – (p)
• d) A – (p), B – (q), C – (r)

Answer: A – (q), B – (p), C – (r)

Question:

• a) A – (r), B – (s), C – (p), D – (q)
• b) A – (s), B – (p), C – (q), D – (r)
• c) A – (r), B – (p), C – (s), D – (q)
• d) A – (q), B – (r), C – (p), D – (s)

Answer: A – (r), B – (s), C – (p), D – (q)

Question:

• a) A – (q), B – (s), C – (p), D – (r)
• b) A – (r), B – (p), C – (q), D – (s)
• c) A – (s), B – (q), C – (p), D – (r)
• d) A – (s), B – (q), C – (p), D – (r)

Answer:   A – (q), B – (s), C – (p), D – (r)

Question:

• a) Assertion is correct, reason is correct; reason is a correct explanation for assertion
• b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
• c) Assertion is correct, reason is incorrect
• d) Assertion is incorrect, reason is correct.

Answer: Assertion is correct, reason is correct; reason is a correct explanation for assertion

Question:

• a) Assertion is correct, reason is correct; reason is a correctexplanation for assertion
• b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
• c) Assertion is correct, reason is incorrect
• d) Assertion is incorrect, reason is correct

Answer: Assertion is correct, reason is correct; reason is a correctexplanation for assertion

Question:

• a) Assertion is incorrect, reason is correct
• b) Assertion is correct, reason is incorrect
• c) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
• d) Assertion is correct, reason is correct; reason is a correct explanation for assertion.

Answer: Assertion is incorrect, reason is correct

Question:

• a) Assertion is correct, reason is correct; reason is a correct explanation for assertion.
• b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
• c) Assertion is correct, reason is incorrect
• d) Assertion is incorrect, reason is correct.

Answer:  Assertion is correct, reason is correct; reason is a correct explanation for assertion.

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d) None of These

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d) None o these

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Two moles of PCl₅ were heated in a closed vessel of 2L. At equilibrium 40% of PCl₅ is dissociated into PCl₃ and Cl₂. The value of equilibrium constant is

• a) 0.267
• b) 5.3
• c) 0.53
• d) 2.63

Answer: 0.267

Question:  PCl₅ is dissociating 50% at 250°C at a total pressure of P atm. If equilibrium constant is K_p, then which of the following relation is numerically correct ?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) 5.82 × 10^–2 atm
• b) 38.8 × 10^–2 atm
• c) 1.94 × 10^–2 atm
• d) 7.66 × 10^–2 atm

Answer: 5.82 × 10^–2 atm

Question:

are in the ratio of 9 : 1. If degree of dissociation of X and A be equal, then total pressure at equilibrium (1) and (2) are in the ratio :

• a) 36 : 1
• b) 3 : 1
• c) 1 : 9
• d) 1 : 1

Answer: 36 : 1

Question:

• a)

  

• b)

  

• c)

  

• d) All of these

Answer:

Question:

• a) K will remain same
• b) K will decrease
• c) K will increase
• d) K will increase initially and decrease when pressure is very high

Answer: K will remain same

Question:

• a) Adding F₂
• b) Increasing the volume of the container
• c) Increasing the temperature
• d) None of these

Answer: Adding F₂

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: In HS^–, I^–, RNH₂ and NH₃, order of proton accepting tendency will be

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question: Which equilibrium can be described as an acid-base reaction using the Lewis acid-base definition but not using the Bronsted-Lowry definition?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Equal volumes of three acid solutions of pH 3, 4 and 5 are mixed in a vessel. What will be the H+ ion concentration in the mixture ?

• a) 3.7 × 10^–4 M
• b) 1.11× 10^–3 M
• c) 1.11 × 10^–4 M
• d) 3.7 × 10^{– 3} M

Answer: 3.7 × 10^–4 M

Question: The pH of 10^–10 M NaOH solution is nearest to

• a) 7
• b) – 10
• c) 6
• d) 4

Answer: 7

Question: 100 mL of 0.04 N HCl aqueous solution is mixed with 100 mL of 0.02 N NaOH solution. The pH of the resulting solution is:

• a) 2.0
• b) 1.0
• c) 1.7
• d) 2.3

Answer: 2.0

Question: Equal volumes of three acid solutions of pH 3, 4 and 5 are mixed in a vessel. What will be the H⁺ ion concentration in the mixture ?

• a) 3.7 × 10^–4 M
• b) 1.11× 10^–3 M
• c) 1.11 × 10^–4 M
• d) 3.7 × 10^{– 3} M

Answer:  3.7 × 10^–4 M

Question: At 100°C the K_w of water is 55 times its value at 25°C. What will be the pH of neutral solution? (log 55 = 1.74)

• a) 6.13
• b) 7.87
• c) 7.00
• d) 5.13

Answer: 6.13

Question:  Ionisation constant of CH₃COOH is 1.7 × 10^–5 if concentration of H⁺ ions is 3.4 × 10^–4M, then find out initial concentration of CH3COOH molecules

• a) 6.8 × 10^–3M
• b) 3.4 × 10^–4M
• c) 3.4 × 10^–3M
• d) 6.8 × 10^–4M

Answer: 6.8 × 10^–3M

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) 3.0 × 10⁴
• b) 3.0 × 10^{– 5}
• c) 3.0 × 10^{– 4}
• d) 3.0 × 10⁵

Answer: 3.0 × 10⁴

Question: If degree of dissociation of pure water at 100°C is 1.8 × 10^–8, then the dissociation constant of water will be (density of H²O = 1 gm/cc)

• a) 1.8 × 10^–14
• b) 1 × 10^–14
• c) 1 × 10^–12
• d) 1.8 × 10^–12

Answer: 1.8 × 10^–14

Question:  Ionisation of weak acid can be calculated by the formula

• a) Both
• b)

  

• c)

  

• d) None of these

Answer: Both

Question: Equimolar solutions of the following were prepared in water separately. Which one of the solutions will record the highest pH ?

• a) BaCl₂
• b) CaCl₂
• c) MgCl₂
• d) SrCl₂

Answer:  BaCl₂

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a)

  

• b)

  

• c) Both
• d) None of these

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question:

• a) 1.386×10^–10
• b) 1.12×10^–11
• c) 3.16×10^–10
• d) 1.45×10^–9

Answer: 1.386×10^–10

Question: pH scale was introduced by

• a) Sorensen
• b) Lowry
• c) Arrhenius
• d) Lewis

Answer: Sorensen