An element A has a triiodide with the formula Al₃and a trichloride with the formula Acl. The triiodide is quantiatively converted to the trichloride when it is heated in a stream of chlorine, according to the reacton

Al₃+ 3/2cl₂→ acl₃+ 3/2I₂

If 0.8000g Al₃ is treated, 0.3776g Acl₃is obtained.

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

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