CHEM 1126Q: Pre-Lab Quiz #2

Calculate the pH of a solution that is 0.50 M in HF (Ka = 7.2 x 10^-4) and 0.63 M in NaF

3.24

Calculate the pH of the following aqueous solution : 0.18 M NH4Cl (pKb for NH3 = 4.74)

5.00

Using the following Ka values, indicate the correct order of base strength. HNO2: Ka = 4.0 x 10^-4 HF: Ka = 7.2 x 10^-4 HCN: Ka = 6.2 x 10^-10

CN- > NO2- > F- > Cl-

A weak acid, HF, is in solution with dissolved sodium fluoride, NaF. If HCl is added, which ion will react with the extra hydrogen ions from the HCl to keep the pH from changing?

F-

Which of the following would produce a basic aqueous solution ?

None

Which of the following would give the highest pH when dissolved in water to form a 0.10 M solution ?

Potassium salt of weak acid

For a solution equimolar in HCN and NaCN, which statement is false?

[H+] is larger than if only HCN is in solution

Which of the following correctly labels the salts? HF (Ka = 7.2 × 10-4) NH3 (Kb = 1.8 × 10-5) HCN (Ka = 6.2 × 10-10) NaCN -> NaOH + HCN NH4F -> NH3 + HF KCN -> KOH + HCN

basic, acidic, basic