The coefficients of any chemical compound are located in the front.
We are asked to find the coefficient of CaCl2 when the equation is balanced. Before finding the coefficient, we should determine if the equation is balanced or not.
Right side: 1 Ca, 2 H, 2 Cl
Left side: 1 Ca, 2 H, 2 Cl → This equation is balanced!
Since the compound CaCl2 has no number in from of the compound, the coefficient has to 1.
Therefore, the coefficient for CaCl2 is 1.