Chapter 12: Q8P-h (page 283)

Consider the titration of 25.0 mL of 0.020 0 M MnSO₄ with 0.010 0 M EDTA in a solution buffered to pH 8.00. Calculate pMn²⁺ at the following volumes of added EDTA and sketch the titration curve:
(a) 0 mL (b) 20.0 mL (c) 40.0 mL (d) 49.0 mL (e) 49.9 mL (f) 50.0 mL (g) 50.1 mL
(h) 55.0 mL (i) 60.0 mL

Short Answer

Expert verified

(h) For 55 mL the value of pMn²⁺is 10.52.

Step by step solution

Introduction

Equations and data obtained in order to proceed for calculation are as follows

$\begin{matrix} T i t r a t i o n Re a c t i o n : M n^{2 +} + E D T A ⇌ M n Y^{2 -} \\ K_{f} = 10^{13.89} \\ A t p H 8 α_{Y^{4 -}} = 4.2 \times 10^{- 3} (T a b l e 12 - 1) \end{matrix}$

Determine equilibrium constant

$\begin{matrix} K_{f}^{'} = α_{Y^{4 -}} \times K_{f} \\ = 4.2 \times 10^{- 3} \times 10^{13.89} \\ = 3.3 \times 10^{11} \end{matrix}$

Equivalence point=50 mL

Determine the value of pMn2+

Past equivalence point (55mL) we need to calculate the metal concentration

There is 5 mL of Excess EDTA

$\begin{matrix} E D T A = (\frac{5}{25 + 55} \times 0.01 M) \\ = 6.25 \times 10^{- 4} M \\ M n Y^{2 -} = (\frac{25}{25 + 55} \times 0.02 M) \\ = 6.25 \times 10^{- 3} M \end{matrix}$

$\begin{matrix} K_{f}^{'} = \frac{[M n Y^{2 -}]}{[M n^{2 +}] [E D T A]} \\ 3.3 \times 10^{11} = \frac{[6.25 \times 10^{- 3}]}{[M n^{2 +}] [6.25 \times 10^{- 4}]} \\ M n^{2 +} = 3.03 \times 10^{- 11} M \end{matrix}$

Therefore, the value of pCu²⁺

^{$\begin{matrix} p M n^{2 +} = - \log (M n^{2 +}) \\ = - \log (3.03 \times 10^{- 13}) \\ = 10.52 \end{matrix}$}

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Short Answer

Step by step solution

Introduction

Determine equilibrium constant

Determine the value of pMn2+

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Consider the titration of 25.0 mL of 0.020 0 M MnSO4 with 0.010 0 M EDTA in a solution buffered to pH 8.00. Calculate pMn2+ at the following volumes of added EDTA and sketch the titration curve:(a) 0 mL (b) 20.0 mL (c) 40.0 mL (d) 49.0 mL (e) 49.9 mL (f) 50.0 mL (g) 50.1 mL(h) 55.0 mL (i) 60.0 mL

Short Answer

Step by step solution

Introduction

Determine equilibrium constant

Determine the value of pMn2+

One App. One Place for Learning.

Most popular questions from this chapter

Recommended explanations on Chemistry Textbooks

Physical Chemistry

Inorganic Chemistry

Nuclear Chemistry

Chemistry Branches

Chemical Reactions

Kinetics

Study anywhere. Anytime. Across all devices.