Question

An organic compound with a formula mass of 417g/molwas analyzed for ethoxyl $\mathbf{(}{\mathbf{CH}}_{\mathbf{y}}{\mathbf{CH}}_{\mathbf{2}}\mathbf{O}\mathbf{-}\mathbf{)}$groups by the reactions

$$\begin{gathered} {\mathbf{ROCH}}_{\mathbf{2}}{\mathbf{CH}}_{\mathbf{3}}\mathbf{+}\mathbf{HI}\mathbf{\to }\mathbf{ROH}\mathbf{+}{\mathbf{CH}}_{\mathbf{3}}{\mathbf{CH}}_{\mathbf{2}}\mathbf{I} \\ {\mathbf{CH}}_{\mathbf{3}}{\mathbf{CH}}_{\mathbf{2}}\mathbf{I}\mathbf{+}{\mathbf{Ag}}^{\mathbf{+}}\mathbf{+}{\mathbf{OH}}^{\mathbf{-}}\mathbf{\to }\mathbf{AgI}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{+}{\mathbf{CH}}_{\mathbf{3}}{\mathbf{CH}}_{\mathbf{2}}\mathbf{OH} \end{gathered}$$

A 25.42-mg sample of compound produced How many ethoxyl groups are there in each molecule?

Short answer

The solution of organic compound contains two ethoxy groups per molecule.

Step-by-step solution

Use organic compound and analyze the ethoxyl groups

Given

Formula mass of an organic compound = 417g/mol

Amount of the sample = 25.42mg

Amount of Silver iodide produced by the sample = 29.03mg

To calculate: number of ethoxy groups is in each molecule

One mole ethoxy group gives one mol Silver iodide.

$29.03\mathrm{mgAgI}=0.12365\mathrm{mmol}$

The quantity of analyzed compound is$=25.42\mathrm{mg}/(417\mathrm{g}/\mathrm{mol})=0.06096\mathrm{mmol}$

$\frac{0.12365\mathrm{mmolethoxy}\mathrm{groups}}{0.06096\mathrm{mmol}\mathrm{compound}}=2.03(\mathrm{twoethoxy}\mathrm{group}/\mathrm{molecule})$

It was found to be there are two ethoxy groups per molecule.