We will balance the equation in the following order: metals, amethals, carbon, hydrogen and oxygen (the most common order). The metal present in the equation is Sr, which is already balanced (there are 1 on each side of the equation). The amethal present in the equation is Cl. There is 2 Cl in the left side and only one in the right side. So, we will multiply the quantity of the molecule that contains Cl by 2. Doing this, we'll obtain: