m.impura = 5 g, puritatea = p = 90%
stim ca p% = m.px100/m.ip
=> mp = m.ipxp%/100 = 5x90/100 = 4,5 g
n moli 4,5 g
2NaOH + HOOC-COOH => NaOOC-COONa + 2H2O
2 90
=> n = 2x4,5/90 = 0,1 moli NaOH
stim ca Cm = niu/Vs
=> Vs = niuxCm = 0,1x0,1 = 0,01 L sol NaOH