The coefficients : 3, 2, 1,3
Given
Reaction
Mg + H3PO4 -> Mg3(PO4)2 + H2
Required
The coefficients
Solution
Steps to balance reactions:
1. Give a coefficient(The most complex compound is assigned a coefficient of 1)
aMg + bH₃PO₄ ⇒ Mg₃(PO₄)₂ + cH₂
2. Make an equation
Mg, left = a, right = 3 ⇒a=3
P, left = b, right = 2⇒b=2
H, left = 3b, right = 2c⇒3b=2c⇒3.2=2c⇒2c=6⇒c=3
The equation becomes :
3Mg + 2H₃PO₄ ⇒ Mg₃(PO₄)₂ + 3H₂