To solve for X, we need to balance the equation using coefficients.

The balanced equation is:

X + 2 Cl2 = C2H2Cl4 + 2X

Since there are only 2 Cl atoms on the left side of the equation and 4 Cl atoms on the right side, we need to add a coefficient of 2 in front of Cl2 on the left side to balance the Cl atoms:

X + 2 Cl2 = 2 C2H2Cl4 + 2X

Now, we can see that there are 2 X atoms on the right side and 1 X atom on the left side of the equation. To balance the X atoms, we need to add a coefficient of 2 in front of X on the left side:

2X + 2 Cl2 = 2 C2H2Cl4 + 2X

Now the equation is balanced, and we can see that X = 2.