What is the ratio of lactic acid (ka = 1.37x10-4) to lactate in a solution with ph =4.54?

Henderson–Hasselbalch equation is given as,

                                         pH  =  pKa  +  log [A⁻] / [HA]    (1)
Solution:
               Convert Ka into pKa

                                         pKa  =  -log Ka

                                         pKa  =  -log 1.37 × 10⁻⁴

                                         pKa  =  3.863

Putting value of pKa and pH in eq.1,

                                         4.54  =  3.863 + log [lactate] / [lactic acid]
Or,
                   log [lactate] / [lactic acid]  =  4.54 - 3.863

                   log [lactate] / [lactic acid]  =  0.677

Taking Anti log,
                             [lactate] / [lactic acid]  =  4.75
Result:
           4.75 M  lactate salt when mixed with 1 M Lactic acid produces a buffer of pH = 4.54.

Aphysical change is one that you can put in and remove like a ham sandwich. the stuff you put in there can be changem its not permanet. a chemical change is on that can't be change thats permanet. like when you make a cake and bake it. you can't get those ingredients back.