What is pH1 M CH_(3)COOHsolution ? To what volumemust onelitre of this solution be diluted so that the pH of resultingso that the pH of resultingsolution will betwicethe orignalvalue . Given :K_(a) = 1.8 xx10^(-5)

What is pH1 M CH_(3)COOHsolution ? To what volumemust onelitre of this

1.	What is pH1 M CH_(3)COOHsolution ? To what volumemust onelitre of this solution be diluted so that the pH of resultingso that the pH of resultingsolution will betwicethe orignalvalue . Given :K_(a) = 1.8 xx10^(-5)
Answer» Solution :`{:(""H_(3)C COOH" "H_(2)O" "hArr" " H_(3)C COO^(-)" +"H_(3)O^(+)),("Initial1M00"),(""-xM""xM""xM),("Final "bar(""(1-x)M""x""x"")):}` `K_(a) = (x^(2))/(1-x)approx(x^(2))/1 :. x = sqrt(K_(a)) = 4.2xx10^(-3) = [ H_(3)O^(+)] ` `PH = - log [H_(3)O^(+)] = - log { 4.2 xx10^(-3)} = 3 - 4.2 = 2.37 ` Now , let 1 L M AcOH solutionbe diluted to V to doublethepH and the conc. of dilutedsolution be C. New`pH = 2 XX OldpH = 2 xx 2.37 = 4.74 ` ` pH = - log [H_(3)O^(+)] = 4.74` `pH = -log [H_(3)O^(+)]= 4.74 ` ` :. [H_(3)O^(+)]= 1.8 xx10^(-5)` `{:(""H_(3)C COOH+H_(2)O hArr H_(3)C COO^(-)""+ ""H_(3)O^(+)),("InitialC00"),(""ul(""-1.8xx10^(-5) "" 1.8xx10^(-5)""1.8xx10^(-5))),("Final" C-1.8xx10^(-5)""1.8xx10^(-5)""1.8xx10^(-5)):}` `K_(a)= ([CH_(3)COO^(-)]xx[H_(3)O^(+)])/([CH_(3)COOH])` ` 1.8 xx 10^(-5) = (1.8 xx10^(-5)xx1.8 xx10^(-5))/(C-1.8xx10^(-5))` ` :. C = 3.6 xx10^(-5) L ` On dilution , `M_(1)V_(1) = M_(2)V_(2)` ` 1 Mxx 1 L= 3.6 xx10^(-5) L xx V_(2)` ` :. V_(2) = 2.78 xx 10^(4) L `