산화-환원 적정. redox titration. 25.8 mL of 0.0214 M K2Cr2O7

산화-환원 적정. redox titration. 25.8 mL of 0.0214 M K2Cr2O7

 

 

The titration of 50.0 mL of saturated solution of sodium oxalate, Na2C2O4, requires 25.8 mL of 0.0214-M K2Cr2O7. Calculate the concentration of the sodium oxalate solution. Assume the reaction occurs in acidic solution.

Cr2O7^2- + C2O4^2- → Cr^3+ + CO2

 

-----------------------------------------

 

균형 맞춘 산화-환원 반응식

Cr2O7^2- + 3C2O4^2- + 14H^+ → 2Cr^3+ + 6CO2 + 7H2O

( 설명 http://ywpop.tistory.com/7380 )

 

 

25.8 mL of 0.0214-M K2Cr2O7에 들어있는 K2Cr2O7의 몰수를 계산하면,

(0.0214 mmol/mL) × 25.8 mL = 0.55212 mmol K2Cr2O7

 

0.55212 mmol K2Cr2O7과 반응한 C2O4^2-의 몰수를 계산하면,

Cr2O7^2- : C2O4^2- = 1 : 3 = 0.55212 mmol : ? mmol

? = 3 × 0.55212 = 1.65636 mmol C2O4^2-

 

C2O4^2-의 몰농도를 계산하면,

1.65636 mmol / 50.0 mL = 0.0331272 M C2O4^2-

 

 

답: 0.0331 M

 

 

[ 관련 글 http://ywpop.tistory.com/2920 ]