In the final chemical equation, hf and o2 are the products that are formed through the reaction between h2o and f2. before you can add these intermediate chemical equations, you need to alter them by multiplying the
a. second equation by 2 and reversing the first equation.
b. first equation by 2 and reversing it.
c. first equation by (1/2) and reversing the second equation.
d. second equation by 2 and reversing it.