In: Chemistry
How many grams of dipotassium succinate trihydrate (K2C4H4O4·3H2O, MW = 248.32 g/mol) must be added to 800.0 mL of a 0.0524 M succinic acid solution to produce a pH of 5.969? Succinic acid has pKa values of 4.207 (pKa1) and 5.636 (pKa2).
no of moles of succinic acid = molarity * volume in L
= 0.0524*0.8 = 0.04192moles
PH = Pka2 + log[K2C4H4O4·3H2O]/[H2C4H4O4·3H2O]
5.969 = 4.207 + log[K2C4H4O4·3H2O]/[H2C4H4O4·3H2O]
log[K2C4H4O4·3H2O]/[H2C4H4O4·3H2O] = 5.969-4.207
log[K2C4H4O4·3H2O]/[H2C4H4O4·3H2O] = 1.762
[K2C4H4O4·3H2O]/[H2C4H4O4·3H2O] = 101.762
[K2C4H4O4·3H2O]/[H2C4H4O4·3H2O] = 57.8
no of moles of K2C4H4O4·3H2O = 57.8*no of moles H2C4H4O4·3H2O
= 57.8*0.04192 = 2.43moles
mass of K2C4H4O4·3H2O = no of moles * gram molar mass
= 2.43*248.32 = 603.4 g >>>> answer