Moles to grams 1_Mg + _2_HCI ---> _1_MgCl2 + _1_H2
What mass of HCl is consumed by the reaction of 1.25 moles of magnesium?

2.5 moles HCl = 2.5moles x 36g/mole HCl = 90 grams HCl.

Explanation:

From equation ratios the reaction ratio is 1 mole Mg to 2 moles HCl. That is, given 1.25 moles Mg, moles HCl consumed will be 2(1.25)moles, or 2.5 moles HCl = 2.5moles x 36g/mole HCl = 90 grams HCl.

first one is the correct answer