You are working in a medical laboratory monitoring the recovery of patients in intensive care. The pH of their blood must be carefully monitored and controlled because even small deviations from normal levels can be fatal. What is the pH of 

(a) Human blood, in which the concentration of H₃O⁺ ions is 4.0 * 10^–8 mol · L^–1; 

(b) 0.020 m HCl(aq); 

(c) 0.040 m KOH(aq)?

ANTICIPATE The concentration of H₃O⁺ ions in blood is lower than in pure water, so you should expect pH > 7; in HCl(aq), an acid, you should expect pH 7.

PLAN The pH is calculated from Eq. 1b. For strong acids, the molar concentration of H₃O⁺ is equal to the molar concentration of the acid. For strong bases, first find the concentration of OH^–, then convert that concentration into [H₃O⁺] by using [H₃O⁺][OH^–] = K_w in the form [H₃O⁺] = K_w/[OH^–].

Transcribed Image Text:

(1b) - = [+0H] 801- pH =