Question

Suppose Fe(SCN)2+ was a gaseous product. What would happen to your determination of Kc if you waited three hours to measure the absorbance values of your equilibrium solution?

Answer 1

Hello

The iron(III) segment in thiocyanatoiron(III)s such as thiocyanatoiron can assimilate a hydroxide into the molecule by substitution:

FeSCN²⁺ + OH⁻ → FeOH²⁺ + SCN⁻

Because of this capture of a hydroxide (OH⁻), thiocyanatoiron has Arrhenius acidic character. In aqueous solution, most thiocyanatoiron is hydrolyzed.

FeSCN²⁺ + H₂O FeOH²⁺ + HSCN

So, if the Fe(SCN)+2 was a gaseous product, it will hydrolyzed with air water molecules (moisture), and The Kc value will be less than expected, due to the fact that the Fe(SCN)2+ with a strong red color will be diminished by the hydrolization.

Some aditional info= The thiocyanic acid , sometimes called sulfociánico acid , exists in aqueous solution as a mixture of thiocyanic acid ( HSCN ) and isothiocyanic acid ( HNCS ) . Thiocyanate compounds are generally salts or esters of thiocyanic acid. When thiocyanic acid is combined with an alcohol can occur a condensation reaction . The hydroxyl group (OH-) of the alcohol is combined with the hydrogen atom ( H + ) of acid to form water ( H2O ) and a thiocyanic or isothiocyanic ester . When the thiocyanic acid reacts with a base , it may be a neutralization reaction . B representing the metal or organic cation , the reaction takes the following form : HSCN + BOH - > BSCN + H20 in which the hydrogen atom is replaced with the cation , creating a thiocyanic or isothiocyanic salt.

Hope iit will help you