Net ionic equations must be balanced by both mass and charge. Balancing by mass means ensuring that there are equal masses of each element on the product and reactant sides. Balancing by charge means making sure that the overall charge is the same on both sides of the equation.
Answer: It requires the heating of a perchloric acid solution and contact EHRS. Explosive perchlorate salts can form in exhaust ducts when perchloric acid is heated.