From the equation below what mass of hydrogen would be produced if 12.0 g of magnesium reacted completely with dilute hydrochloric acid? (H = 1, Mg = 24)

Mg2 + 2HCI(aq) → MgCI2(g) + H2(g)

A. 1.0g
B. 2.0g
C. 6.0g
D. 12.0g
E. 24.0g

Correct Answer: Option A
Explanation

Mg2 + 2HCI(aq) → MgCI2(g) + H2(g)

24g of Mg2 reacts with 2g H2

therefore, 1g of Mg will react with = 2/24g H2

12g Mg2 = 2/24×12g H2

= 1g H2.