In order to determine which option is a strong acid, we must understand the definition and characteristics of strong acids. Strong acids are those that completely dissociate into their ions in water. This means that in solution, they release a large number of hydrogen ions, resulting in a high level of acidity.
Let's evaluate each of the options provided:
Therefore, the correct answer is HCl, as it is the only option that is a strong acid, capable of complete dissociation in aqueous solution.
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?