Question

Match the pKa (determined in an unknown mixture of water and an organic solvent) with the correct acid:

Match the pka (determined in an unknown mixture of water and an organic solvent) with the correct acid: N= -CH3 ОН. A D Food 요 F3C OH H3C H B E o Eto OEt O2N-CH3 C F 1. 0.8 II. 19.4 v What is the pka of A? v What is the pka of B? v What is the pka of C? v What is the pka of D? III. 28 IV. 15.7 v What is the pka of E? V. 10.0 VI.5.2 v What is the pka of F?

Answer 1

1) pka of A ( Acetonitrile )  = ( III)28

2) pka of B (Trifluroacetic acid ) = (I) 0.8

3) pka of C (Diethylmalonate ) = (IV) 15.7

4) pka of D (Benzoic acid ) =(VI) 5.2

5) pka of E( Acetaldehyde )  =( II) 19.4  

6) pka of F ( Nitromethane) = (V)10

Overall all pka is pH at which 50% molecules gets protonated . Pka can be calculated by titration with water or solvent with acid and base . pka of corresponding compound can be watched on the basis of   literature value of pka .