The pH of a solution containing 0.20M CH_(3)COOH and 0.30M CH_(3)COONa

1.	The pH of a solution containing 0.20M CH_(3)COOH and 0.30M CH_(3)COONa is
Answer» `2.89` `4.92` `5.04` `3.89` Solution :SINCE we are dealing with a mixture of a weak ACID and its salt with a strong base, we can calculate the pH of the solution by using the Henderson-Hasselbalch EQUATION: `pH=pK_(a)+"log"(C_("salt"))/(C_("acid"))` In this CASE, we need to calculate `pK_(a)` and the acid FIRST: `pK_(a)= -logK_(a)` `= -log(1.8xx10^(-5))` `=4.74` Now, we substitute the value of `pK_(a)` and concentrations of the acid and its salt: `pH=pK_(a)+"log"(C_("salt"))/(C_("acid"))` `=4.74+"log"(0.30)/(0.20)` `=4.74+log(1.5)` `=4.92`

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