Answer: second option: mole ratio.
Explanation:
The coefficients of the chemical equation, when balanced, indicate the number ratio in which compounds combine with each other.
In the given equation, Mg+2HCl -->MgCl₂+H₂
1 mole of Mg combines with 2 moles of HCl and produce 1 mole of MgCl₂ and 1 mol of H2.
So, the mole ratio is
1 mol Mg : 2 mol HCl : 1 mol MgCl₂ : 1 mol H₂.
In general, in a balanced equation of the kind aA + bB → cC + dD
The mole ratio is:
a mol of A : b mol of B : c mol of C : d mol D.
