40 mL of 0.1 M ammonia solution is mixed with 20 mL of 0.1 M HCl.

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40 mL of 0.1 M ammonia solution is mixed with 20 mL of 0.1 M HCl. What is the pH of the mixture? ( pKb of ammonia solution is 4.74)

Options

(a) 4.74
(b) 2.26
(c) 9.26
(d) 5

Correct Answer:

9.26

Explanation:

40mL of 0.1 M ammonia solution = 40×0.1
= 4 milli equivalent ammonia solution,
20 mL of 0.1 M HCl = 20×0.1,
= 2 milliequivalent of HCl,
NH₄OH + HCl → NH₄Cl + H₂O. Initial milli.eqv. 4 2 0. Milli-eqv.after 4-2 0 2 reaction = 2. Therefore pOH = pK(b) + log[NH₄Cl]/NH₄OH] = 4.74 + log2/2
= 4.74 + log 1 = 4.74.
Therefore pH = 14 – 4.74 = 9.26.

Related Questions:

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2. What is the pH of the resulting solution when equal volumes of 0.1 M NaOH
3. The wavelength of the radiation emitted when an electron drops from 3rd orbit
4. Which of the following statements is incorrect
5. The fractional distillation is used in

Topics: Equilibrium (104)
Subject: Chemistry (2512)

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