Physical Chemistry MCQ with Answers

Physical Chemistry MCQ with Answers

241) When equal volumes of the solutions are mixed, precipitation of AgCl (K_sp = 1.8 x 10⁻¹¹) will occur with:

Answer is:

10⁻⁴M Ag⁺ + 10⁻⁴M Cl⁻

Explanation:

Precipitation occurs when ionic product > solubility product.

242) pK_a values of two acids A and B are 4 and 5. The strengths of these two acids are related as:

Answer is:

Acid A is about 3 times stronger than acid B

243) A buffer solution has equal volumes of 0.2M NH₄OH and 0.02M NH₄Cl. The pK_b of the base is 5. The pH is:

Answer is:

10

Explanation:

pOH = pK_b + log ([salt]⁄[base])

244) The number of OH⁻ ions in 1 mL of solution having pH = 4 is:

Answer is:

6.02 x 10¹⁰

Explanation:

[H⁺] [OH⁻] = 10⁻¹⁴

245) For preparing a buffer solution of pH 6 by mixing sodium acetate and acetic acid, the ratio of the concentration of salt and acid should be: (K^a = 10⁻⁵)

Answer is:

0.417361111

Explanation:

pH = pK_a + log([salt]⁄[acid])

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