Three different reactions were started with identical initial concentration of reactants. Which of the following statement is correct regarding the given graph showing variation of reactant concentration with time?
The rate constant of reaction 3 is larger than the rate constant of reaction 2 if the order of reaction is same for both.
The SI unit of rate constant of reaction 1 is \(s^{-1}\).
Thermal decomposition of HI on gold surface is an example of reaction 2.
Show Solution
Verified By Collegedunia
The Correct Option isB
Solution and Explanation
Step 1: Understanding the Concept:
The concentration vs time graph helps identify the order of a reaction and compare rate constants. A linear decrease indicates a zero-order reaction, while curves indicate higher orders.
Step 3: Detailed Explanation:
Curve 1 is a straight line, which represents a zero-order reaction where \([R] = [R]_0 - kt\).
Curves 2 and 3 are non-linear, representing first or second-order reactions.
- Statement (A) is incorrect because the shapes (linear vs curved) clearly indicate different orders.
- Statement (B) is correct: For curves with the same shape (order), the one that drops faster (Curve 3 is steeper than Curve 2) corresponds to a higher rate of reactant consumption, implying a larger rate constant \(k\).
- Statement (C) is incorrect because the SI unit for a zero-order rate constant is \(mol \cdot L^{-1} \cdot s^{-1}\), not \(s^{-1}\).
- Statement (D) is incorrect because the thermal decomposition of HI on a gold surface is a well-known example of a zero-order reaction (Reaction 1), not Reaction 2.
Step 4: Final Answer:
The correct statement is (B).
