Consider the reaction X + Z ? Assume the following:
1) The product is an ionic compound.
2) Element X has three valence electrons
3) Element Z needs two valence electrons to have completed s & p subshells (full octet)
What would make the most sense for the formula of the product?

X2Z3

Explanation:

Based on the clues, X is a metal and Z is a non-metal.

X could be aluminum and Z would need to be an element from the oxygen family.

you didnt put any of the following

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