Question

For a first-order reaction, $A\to Product$, the initial concentration of A is 0.1M and after 40 minutes it becomes 0.025 M. Calculate the rate of reaction at reactant concentration of 0.01 M:

• A. $3.47\times {10}^{-4}M.mi{n}^{-1}$
• B. $3.47\times {10}^{-5}M.mi{n}^{-1}$
• C. $1.735\times {10}^{-6}M.mi{n}^{-1}$
• D. $1.735\times {10}^{-4}M.mi{n}^{-1}$

Answer 1

Answer: (A)

$3.47\times {10}^{-4}M.mi{n}^{-1}$

As we know,

$K=\frac{2.303}{40}log\frac{\left[0.1\right]}{\left[0.025\right]}$

$\therefore K=0.03466mi{n}^{-1}$

$\therefore rate=K\times 0.01=0.03466\times 0.01=3.47\times {10}^{-4}Mmi{n}^{-1}$