When the Concentration of a Is Doubled,the Rate for the Reaction

question 162

Multiple Choice

When the concentration of A is doubled,the rate for the reaction: 2 A + B → 2 C quadruples. When the concentration of B is doubled the rate remains the same.Which mechanism below is consistent with the experimental observations?

• A)Step 1: A + B ⇌ D (fast equilibrium)
• Step 2: A + D → 2 C (slow)
• B)Step 1: A + B → D (slow)
• Step 2: A + D ⇌ 2 C (fast equilibrium)
• C)Step 1: 2 A → D (slow)
• Step 2: B + D → E (fast)
• Step 3: E → 2 C (fast)
• D)Step 1: 2 A ⇌ D (fast equilibrium)
• Step 2: B + D → E (slow)
• Step 3: E → 2 C (fast)