Show your work in detail and explain for each problems. Circling answer only do

Question

Show your work in detail and explain for each problems. Circling answer only do not get any points.

1. Determine the pH of a KOH solution made by mixing 0.251 g KOH with enough water to make 1.0 × 102 mL of solution. A) 1.35 B) 2.35 C) 7.00 D) 11.65 E) 12.65

2. Calculate the pH of a 3.5 × 10–3 M HNO3 solution. A) –2.46 B) 0.54 C) 2.46 D) 3.00 E) 3.46

3. Diet cola drinks have a pH of about 3.0, while milk has a pH of about 7.0. How many times greater is the H3O+ concentration in diet cola than in milk? A) 2.3 times higher in diet cola than in milk B) 400 times higher in diet cola than in milk C) 0.43 times higher in diet cola than in milk D) 1,000 times higher in diet cola than in milk E) 10,000 times higher in diet cola than in milk

4. A 5.5 L sample of a 0.25 M HNO3 solution is mixed with 1.2 L of a 0.34 M HCl solution. What is the pH of the mixture? A) 0.23 B) 0.57 C) 1.07 D) 0.50 E) 0.84

5. Predict the direction in which the equilibrium will lie for the reaction H3PO4(aq) + HSO4–(aq) H2PO4–(aq) + H2SO4(aq). Ka1(H3PO4) = 7.5 × 10–3; Ka(H2SO4) = very large A) to the right B) to the left C) in the middle

6. Predict the direction in which the equilibrium will lie for the reaction H2SO3(aq) + HCO3– (aq) HSO3–(aq) + H2CO3(aq). Ka1(H2SO3) = 1 × 10–2; Ka1(H2CO3) = 4.2 × 10–7 A) to the right B) to the left C) in the middle

7. Which one of these salts will form a basic solution upon dissolving in water? A) NaI B) NaF C) NH4NO3 D) LiBr E) Cr(NO3)3

8. Which one of these salts will form an acidic solution upon dissolving in water? A) LiBr B) NaF C) NH4Br D) KOH E) NaCN

9. Which one of the following salts will form an acidic solution on dissolving in water? A) LiBr B) NaF C) KOH D) FeCl3 E) NaCN

Explanation / Answer

1. PH of KOH solution, 0.251 g of KOH dissolved in 100 mL of water.

Concentration of KOH= wt. of KOH x 1000 mL/ Mol. wt. of KOH x 100 mL= 0.251 x 1000 / 56.10 x 100= 0.0447 M

POH= -log [OH-]= -log [0.0447]= 1.349

PH=14-POH= 14-1.349= 12.651

Option E, 12.65 is the answer.

2. The pH of a 3.5 × 10–3 M HNO3 solution.

PH=-log[H+]= - log[0.0035]= 2.46

Option C) 2.46 is the answer.

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