Question

the time required for the 100% completion of a first order reaction if its half life is 100 minute is​

Answer 1

Given:

Half life of reaction, T1/2 = 100 minutes.

Order of reaction = 1

To Find:

The time required for the 100% completion of reaction.

Calculation:

-We know that for a first order reaction, the formula is:

t = (2.303/k) log [R]₀/[R]

- For 100% completion, the amount of reactants left is zero, i.e., [R] = 0

- From the above equation, we have:

t = (2.303/k) log [R]₀/0

⇒ t = (2.303/k) log ∞

⇒ t = ∞

- Hence, for a first order reaction, it requires infinite amount of time for the reaction to be 100% complete.

Answer 2

The time required for 100% completion of any first order reaction is infinite.

• For a first order reaction, kt= ln(Ai/At).
• Half life of a reaction is the time in which the concentration of the reactants becomes half of the initial concentration.
• When the reaction is 100% complete, At=0, hence infinite time will be the required for the reaction to be completed.
• Therfore, no reaction can reach 100% completion.