欲由HAc和NaOH两溶液配制pH=5.0的缓冲溶液,问需0.100mol.L-1（-1是上标）HAc溶液与0.100mol.L-1NaOH溶液的体积比.已知HA pKa=4.75

设需要HAcV1L;NaOH V2L;混合后：HAc浓度=（0.1V1-0.1V2）/(V1+V2); NaAc浓度=（0.1V2）/(V1+V2);pH=pKa+lg(c(NaAc)/c(HAc));5=4.75+lg((0.1V2)/(0.1V1-0.1V2));V2/（V1-V2）=1.78;V1/V2=1.56;