Chapter 18, Problem 18.66QP

Interpretation Introduction

Interpretation:

The balanced equation for the reaction between ${\text{Cr}}_{\text{2}}{\text{O}}_7{}^{2-}$ and ${\text{Fe}}^{\text{2+ }}$ has to be found and the molar concentration of ${\text{Fe}}^{\text{2+ }}$ in the given solution has to be calculated.

Concept Introduction:

Redox reactions are the reactions in which both oxidation and reduction takes place simultaneously.  Oxidation is the removal electron from an atom or ion.  Oxidation process increases the oxidation number.  Reduction is the addition of electron to an atom or ion.  Reduction process decreases the oxidation number.  The electrochemical reaction of zinc with copper sulphate is an example of redox reaction.

${\text{Zn(s)+CuSO}}_{\text{4}}\text{(aq)}\to {\text{ZnSO}}_{\text{4}}\text{+Cu(s)}$

Mole is the mass of the substance that is having Avogadro number of particles.  The number of moles of a given substance can be calculated by multiplying its volume with concentration

Molar concentration or molarity is the ratio of number of moles of solute to the volume of the solution in litre.