Match the following industrial processes with the catalysts used:

Cracking of hydrocarbons – Fe
Each process is paired with its appropriate catalyst, enhancing the reaction's efficiency. For example, Ostwald's process uses \( \text{CuCl}_2 \) to produce nitric acid from ammonia.
For the reaction \( A + B \to C \), the rate law is found to be \( \text{rate} = k[A]^2[B] \). If the concentration of \( A \) is doubled and \( B \) is halved, by what factor does the rate change?