Chapter 2, Problem 32P

An element A has a triiodide with the formula ${\text{AI}}_{\text{3}}$ and atrichloride with the formula ${\text{ACl}}_{\text{3}}$ . The triiodide is quantitativelyconverted to the trichloride when it is heated in astream of chlorine, according to the reaction

${\text{AI}}_{\text{3}}+\frac{\text{3}}{2}{\text{Cl}}_{\text{2}}\to {\text{ACl}}_{\text{3}}+\frac{3}{2}{\text{I}}_{\text{2}}$

If $0.\text{8}000{\text{ g AI}}_{\text{3}}$ is treated, $0.{\text{3776 g ACl}}_{\text{3}}$ is obtained.

(a) Calculate the atomic mass of the element A.

(b) Identify the element A.