Which molecule could have an expanded octet? hno2 h2co3 h3po4?

 is the molecule that can have an expanded octet.

Octet Expansion:

It means that the molecule or atom needs more electron than they require in octet rule.

has 32 valence electrons in its outermost shell instead of 8 valance electrons.

Therefore, is the molecule that have expanded octet.

To know more about Octet expansion,

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it would be a gas formation

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