C2_22H2_22 + yH2_22 → C2_22H6_66
To balance the equation, we must have 2 carbon atoms on both sides and 6 hydrogen atoms.
On the LHS and RHS, carbon = 2 atoms.
On the LHS, Hydrogen = 2 + 2y.
On the RHS, Hydrogen = 6.
⇒ 2 + 2y = 6
2y = 4
y = 2.