Question

Post Lab Activity Acids, Bases, pH, and Buffers 1. Calculate the pH of a 0.08 M NaOH solution. 2. Hydrochloric acid is a strong acid and dissociate almost 100% in aqueous solution. If two drops (0.1 mL) of 1.0 MHCI are added to pure water to make 1.0 L solution. What is the pH of this solution? 3. M. What will be the A dilute solution of hydrochloric acid (HCI) has a concentration of 0.1 pH of this solution? 4. Human blood is slightly basic in nature with a normal pH range of 7.35-7.45. The blood pH is maintained by the carbonic acid-bicarbonate buffer system, shown by the following equilibrium reaction. | H2CO3 + H2O = HO* + HCO If you add a small amount of an acid to this buffer, then which component of the carbonic acid-bicarbonate buffer will react with the added acid? Explain. a) b) If you add a small amount of a base to this buffer, then which component of the carbonic acid-bicarbonate buffer will react with the added base? Explain. c) Why the pH of buffer solution remains constant when a small amount of acid or base is added to it?

Answer 1

Narth (aq) - Nah (aq) + oH aq (6H] = [Nacu) = 0.08 m. pOH = -log CoH ] = -log (0.08) = W10 Now, pH = 14.0- por = 14.0 -:10 = 12.91 M, = tom No=o.lmL Na = 10L = 1000mL | M = mitial molarity M₂ = final molanity Vi= initial volume I U₂ = final volume Movi= Me V₂ or ov M MV, Mr V2 = lomxo.1mL -= 0.0001m 1000ML Thus, wolarity of the final solution = 0.0001m HU (one) — H+ (aq) + OH- (ap) (H+] = [HU] = 0.00017 pH = -log[ht] s-log (0.6001) = 4.07

3. Hu Cae) — Ht@q) + oH faqe [H+] - Hu] - 01 - 2 - 10 x10 m Since the concentration is very low, we have to consider the Ht form conisation of water too. H2O(1) H*@g)+ oH" @ for water, [H+] = [0HJ = 10x15'm Total CH"] = (1-0 x16”m) + (1-0x16’m) 2:0010 m PH = -log(H+) = -log (2_0x10") = 16-7] 7