PHYSICAL CHEMISTRY IN BRIEF

CHAP. 11: ELECTROCHEMISTRY [CONTENTS] 381 11.5.10Hydrolysis of the salt of a weak acid and a weak base The salt of a weak monoac ...

CHAP. 11: ELECTROCHEMISTRY [CONTENTS] 382 11.6 Calculation of pH 11.6.1 Definition of pH. The quantity pH is defined by the rela ...

CHAP. 11: ELECTROCHEMISTRY [CONTENTS] 383 Solution At 0◦C the ionic product of water isKw= 1. 25 × 10 −^15. Substituting into (1 ...

CHAP. 11: ELECTROCHEMISTRY [CONTENTS] 384 11.6.4 pH of a strong monobasic acid. For a strong monobasic acid HA it applies thatcH ...

CHAP. 11: ELECTROCHEMISTRY [CONTENTS] 385 Solution At a concentration as low as this, the activity coefficient of hydrogen ions ...

CHAP. 11: ELECTROCHEMISTRY [CONTENTS] 386 wherecis the acid concentration andαis the degree of dissociation in the second stage. ...

CHAP. 11: ELECTROCHEMISTRY [CONTENTS] 387 whereKis the dissociation constant of the acid. If the dissociation degree is low,α &l ...

CHAP. 11: ELECTROCHEMISTRY [CONTENTS] 388 The acid concentration is very low,c= 10−^6 in order. At very low concentrations a we ...

CHAP. 11: ELECTROCHEMISTRY [CONTENTS] 389 If the conditions are not as above, we have to take into account dissociation in the s ...

CHAP. 11: ELECTROCHEMISTRY [CONTENTS] 390 11.6.11pH of the salt of a strong acid and a weak base In consequence of hydrolysis, s ...

CHAP. 11: ELECTROCHEMISTRY [CONTENTS] 391 We obtain the pH of a buffer solution formed by a weak acid HA of the concentrationcan ...

CHAP. 11: ELECTROCHEMISTRY [CONTENTS] 392 Thebuffer capacityof a buffer,βb, related to the added base is defined by the relation ...

CHAP. 11: ELECTROCHEMISTRY [CONTENTS] 393 11.7 Solubility of sparingly soluble salts If the concentration of a saturated solutio ...

CHAP. 11: ELECTROCHEMISTRY [CONTENTS] 394 Solution a) We have Ag 2 CrO 4 (s) = 2 Ag++ CrO^24 −. From the material balance it fol ...

CHAP. 11: ELECTROCHEMISTRY [CONTENTS] 395 Solution From the material balance it follows thatcAg+ = 2c andcCrO 24 − = c+ 0. 01 , ...

CHAP. 11: ELECTROCHEMISTRY [CONTENTS] 396 11.8 Thermodynamics of galvanic cells 11.8.1 Basic terms Agalvanic cellis an electroch ...

CHAP. 11: ELECTROCHEMISTRY [CONTENTS] 397 Example The Daniell cell is an example of a galvanic cell. It is formed by two half-ce ...

CHAP. 11: ELECTROCHEMISTRY [CONTENTS] 398 With the electrolyte we note its molality or activity in brackets. This may be omitte ...

CHAP. 11: ELECTROCHEMISTRY [CONTENTS] 399 The following relation applies between electrical work and a change in the Gibbs energ ...

CHAP. 11: ELECTROCHEMISTRY [CONTENTS] 400 whereaiis the activity of substancei. Relation (11.111) is called theNernst equationfo ...