Verified Solution • 2025–26 Session moderate

QJEEM19Ch7644: JEE Main 2019 Chemistry - Class 11 JEEM19Ch7644 Solution: Consider the following statements (a) The pH of a mixture…

Consider the following statements
(a) The pH of a mixture containing 400 mL of 0.1 M H2SO4 and 400 mL of 0.1 M NaOH will be approximately 1.3
(b) Ionic product of water is temperature dependent.
(c) A monobasic acid with Ka = 10–5 has pH = 5. The degree of dissociation of this acid is 50 %.
(d) The Le Chatelier's principle is not applicable to common-ion effect.

The correct statements are :

Multiple Choice Options

  • A (a) and (b)
  • B (a), (b) and (c)
  • C (a), (b) and (d)
  • D (b) and (c)

Step-by-Step Verified Solution

(a) Equivalance of strong acid = 0.1 × 2 × 400 = 80

Equivalance of strong base = 0.1 × 400 = 40

∴ [H+] of mixture = 80−40800 = 120

∴ pH = −log⁡[H+] = −log⁡(120) = 1.3

(b) Ionic product of water increases with increase of temperature because ionisation of water is endothermic.

(c) JEE Main 2019 (Online) 10th April Morning Slot Chemistry - Ionic Equilibrium Question 82 English Explanation

ka = 10−5×cαc(1−α)

⇒ 10-5 = 10−5×α(1−α)

⇒ α(1−α) = 1

⇒ α = 0.5

∴ Degree of dissociation(α) = 50%

(d) The Le Chatelier's principle is always applicable to common-ion effect.

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