A reaction is first order in A. If the rate constant of the reaction is 3.45x10^-3 s-1, what is the half life of the reaction?

a. 4.98x10^-3 s
b. 200 s
c. 3.45x10^-3 s
d. 100 s
e. 1.73x10^-3 s

B. 200

To determine the half-life of a first-order reaction, we can use the formula:

t_1/2 = (0.693 / k)

where:
t_1/2 is the half-life of the reaction
0.693 is the natural logarithm of 2 (ln(2))
k is the rate constant of the reaction

In this case, the rate constant of the reaction is given as 3.45x10^-3 s^-1.

Now we can substitute the given values into the formula to find the answer:

t_1/2 = (0.693 / 3.45x10^-3)

To simplify this expression, divide 0.693 by 3.45x10^-3:

t_1/2 ≈ 200 s

Therefore, the correct answer is option (b) 200 s.

To determine the half-life of a first-order reaction, you can use the following equation:

t1/2 = ln(2) / k

where t1/2 is the half-life, ln is the natural logarithm, and k is the rate constant.

Given that the rate constant (k) is 3.45x10^-3 s^-1, we can substitute this value into the equation:

t1/2 = ln(2) / (3.45x10^-3 s^-1)

Calculating this expression, we find:

t1/2 = 0.693 / (3.45x10^-3 s^-1)

t1/2 ≈ 200 s

Therefore, the correct option is b. 200 s.