Question

10. Fill in each blánk with increases or decreases As K, increases, acid strength As Kb increases, base strength As pK, increases, acid strength As pKb increases, base strength As acid strength increases, conjugate base strength The stronger an acid, the the conjugate base. (stronger or weaker) HoCI NH4 11. a) Which is the HS stronger acid? stronger acid? stronger base? stronger base? HF pk-3.14 CH,OH pk, 10.0 b) Which is the c) Which is the d) Which is the CH3COOH K 1.8 x 10 CH COO NO3 CH CoO 12. a) Label the acid and base on the reactant side and on the product side. b) Predict the direction in which each of the acid/base reactions will proceed. (You may wish to use data from problems 9 & 11). i) HF + NH, NH,' + F ii) CIO4 CH COOHHCIO4 +CH,COO 13. Calculate the value of both pH and pOH of the following solutions. a) 0.020 M HCI b) 0.0050 M NaOH c) A specimen containing 7.2 x 101 H' mole'L. Is the specimen slightly acidic or slightly basic? d) 0.00035 M Ba(OH)2, where this compound has to be considered to be l 00% dissociated. 14. Calculate theHO'.TOH] pH and pOH of these solutions 1.0 M HCI 0.50 M HNO 0.0020 M HCIO 1.5 X 10 M KOH a solution prepared by dissolving 0.040gNaOH in 2.0 L of solution a solution prepared by diluting 1.0 mL of 0.20 M HCl to a total volume of 5.0 L a solution made by dissolving 0.10 mol Na-O in 1.0 L of water

Answer 1

Question 10.

a. Increases.

Explanation: The acid (HA) dissociation constant Ka = [H^+][A^-]/[HA]. The increase in Ka leads to increase in [H^+], which leads to increase in acidic strength.

b. Increases.

c. Decreases.

Explanation: pKa = -Log(Ka). The increase in pKa leads to decrease in Ka, hence acidic strength decreases.

d. Decreases.

e. Decreases.

Explanation: CH3COOH(aq) $\rightleftharpoons$ CH3COO^-(aq) + H^+(aq)

Here, CH3COOH is is a weak acid, whereas CH3COO^- is the corresponding conjugate base, which is strong.

HCl(aq) ----> H^+(aq) + Cl^-(aq)

Here, HCl is a strong acid, whereas Cl^- is the corresponding conjugate base, which is weak.

f. Weaker