Q1: The units of the rate constant for a second order reaction are

ANS:C - moles^-1. sec¹.

The units of the rate constant for a second-order reaction are moles⁻¹.sec⁻¹. Explanation: In a second-order reaction, the rate of the reaction is proportional to the square of the concentration of one reactant or to the product of the concentrations of two reactants. The general form of a second-order reaction rate equation is: rate=k[A]n[B]m Where:

• k is the rate constant.
• [A] and [B] are the concentrations of reactants A and B, respectively.
• n and m are the orders of the reaction with respect to reactants A and B, respectively. For a second-order reaction, either n or m (or both) is equal to 1.

Since the rate constant k has to make the units on both sides of the equation consistent, it must have units that cancel out the units of concentration raised to the power of the reaction order. For a second-order reaction, where the concentration is in moles per liter (mol/L), and the reaction rate is in moles per liter per second (mol/L.sec), the units of the rate constant k must be: moles−1×sec−1 Therefore, the units of the rate constant for a second-order reaction are moles⁻¹.sec⁻¹.