Question

急 将45ml.0.1mol/l的HCl溶液跟5mL 0.5mol/L的氢氧化钠溶液混合后稀释到500mL,在常温下所得

Answer 1

n(HCl)=0.045*0.1=0.0045mol n(NaOH)= 0.5*0.005=0.0025mol

HCl + NaOH ==== NaCl + H2O

1mol 1mol

0.0045mol 0.0025mol

HCl过量,0.0045-0.0025=0.002mol

C(H+)=0.002/0.5=0.004=4*10^-3

PH=-lg(H+)=-lg(4*10^-3)=3-lg4