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A 25.00mL sample of unknown containing Fe3+ an
问题详情
A 25.00mL sample of unknown containing Fe3+ and Cu2+ required 16.06mL of 0.05083mol·L-1 EDTA for complete titration. A 50.00mL sample of the unknown was treated with NH4F to protect the Fe3+. Then the Cu2+ was reduced and masked by addition of thiourea. Upon addition of 25.00mL of 0.05083mol·L-1 EDTA，the Fe3+ was liberated from its fluoride complex and formed an EDTA complex. The excess EDTA required 19.77mL of 0.01883mol·L-1 Pb2+ to reach an endpoint using xylenol orange. Find the concentration of Cu2+ in the unknown.
参考答案
c(Cu2+)={[0.05083×16.06-(0.05083×25.00-0.01883×19.77)/2]/25.00}mol·L-1
=0.01468mol·L-1
