Question

What is the order of a reaction if the rate constant unit is \(L \cdot mol^{-1} \cdot s^{-1}\)?

• A. Zero order
• B. First order
• C. Second order
• D. Third order

Hint:

For reaction order \(n\): \[ k \propto (mol/L)^{1-n} \] Match the exponent to quickly determine the order.

Answer 1

The Correct Option is C

Concept: The unit of rate constant \(k\) for an \(n^{th}\) order reaction is given by \[ k = (mol/L)^{1-n} \cdot s^{-1} \]

Step 1: Compare given unit with general formula. Given: \[ k = L \cdot mol^{-1} \cdot s^{-1} = (mol/L)^{-1} \cdot s^{-1} \]

Step 2: Equate powers. \[ 1 - n = -1 \] \[ n = 2 \] \[ \boxed{\text{Second Order}} \]