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GS
GS Set-1
Chemistry
Physical Chemistry
240

Physical Chemistry MCQ with Answers

240) If pK_{a_{of acetic acid at 25^oC is 4.75, then determine the pH of that solution in which 0.02M sodium acetate and acetic acid are present:}}

4.75

3.75

5.75

2.75

Answer is:

4.75

Explanation:

[salt] = [acid]

Physical Chemistry MCQ with Answers

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

10⁻⁴M Ag⁺ + 10⁻⁴M Cl⁻

10⁻⁵M Ag⁺ + 10⁻⁵M Cl⁻

10⁻⁶M Ag⁺ + 10⁻⁶M Cl⁻

10⁻¹⁰M Ag⁺ + 10⁻¹⁰M Cl⁻

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:

Strength of acid A : Strength of acid B = 4 : 5

Acid A is about 3 times stronger than acid B

Acid B is 10 times stronger than acid A

The strengths of the two acids cannot be compared

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:

10⁻⁴

10⁻¹⁰

6.02 x 10¹⁰

6.02 x 10¹³

Answer is:

6.02 x 10¹⁰

Explanation:

[H⁺] [OH⁻] = 10⁻¹⁴

Physical Chemistry MCQ with Answers

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240) If pKa of acetic acid at 25oC is 4.75, then determine the pH of that solution in which 0.02M sodium acetate and acetic acid are present:

4.75

Physical Chemistry MCQ with Answers

Related Physical Chemistry MCQ with Answers

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

10−4M Ag+ + 10−4M Cl−

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

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 pKb of the base is 5. The pH is:

10

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

6.02 x 1010

Physical Chemistry MCQ with Answers

240) If pK_{a_{of acetic acid at 25^oC is 4.75, then determine the pH of that solution in which 0.02M sodium acetate and acetic acid are present:}}

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

10⁻⁴M Ag⁺ + 10⁻⁴M Cl⁻

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

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:

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

6.02 x 10¹⁰