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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

Answer 1

3. E) 10,000 times higher in diet cola than in milk

pH = - log [H3O+]

For diet cola, pH = 3 then H3O+ concentration will be 10^-3 M

For milk, pH = 7 then H3O+ concentration will be 10^-7 M

Substract both concentrations, 10^-3 M / 10^-7 M = 10⁴ = 10,000 times.

4. B) 0.57

First we will find out the number of moles of H+ in 6.7 L,

Moles of H+ in 6.7 Lit acid solution = (5.5 x 0.25) + (1.2 x 0.34) = 1.783 moles

So, concentration of H+ = 1.783 moles / 6.7 L = 0.266

We know,

pH = - log [H3O+] = - log (0.266) = 0.575

5. B) to the left

If the ka value is large, then the acid will be stronger. Hence, it will dissociate (or) release H+ readily compared to the other one. H2SO4 is the stronger acid.

6. A) to the right

If the ka value is large, then the acid will be stronger. Hence, it will dissociate (or) release H+ readily compared to the other one. H2SO3 is the stronger acid here.

7. B) NaF

Na+ will be converted into NaOH, a strong base. F- will be converted into HF, a weak acid. Hence the resultant solution will be basic. Other haloacids are stronger than HF.

8. C) NH4Br

NH4+ will be converted into NH4OH, a weak base. Br- will be converted into HBr, a strong acid. Hence the resultant solution will be acidic.

9. D) FeCl3

Fe3+ will be converted into Fe(OH)3, a weak base. Cl- will be converted into HCl, a strong acid. Hence the resultant solution will be acidic.