An ion has the following Lewis structure where X is an unknown element. Which of the following elements could be X? (Select all that apply.) Kr Br Xe F Cl Ne

Br, Cl

Explanation:

Several families of halogen oxides are known which give rise to different anions such as the one pictured in the image attached to the question which I can not be able to reproduce here.

This type of anions are commonly formed by chlorine, bromine and iodine. These anions  are formed when the octet of the halogen is expanded. This implies that the outermost shell of the halogen now contains more than eight electrons.

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2