Question

Half life is expressed as T₁/₂= ?


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Answer 1

Answer:

What is Reaction Half-Life?

The half-life of a chemical reaction can be defined as the time taken for the concentration of a given reactant to reach 50% of its initial concentration (i.e. the time taken for the reactant concentration to reach half of its initial value). It is denoted by the symbol ‘$t_{1/2}$’ and is usually expressed in seconds.

Half-Life Formula

It is important to note that the formula for the half-life of a reaction varies with the order of the reaction.

For a zero-order reaction, the mathematical expression that can be employed to determine the half-life is: $t_{1/2}$ = $[R_o]/2k$

For a first-order reaction, the half-life is given by: $t_{1/2}$ = 0.693/k

For a second-order reaction, the formula for the half-life of the reaction is: $1/K[R]_o$

Where,

$t_{1/2}$ is the half-life of the reaction (unit: seconds)

[$R_0$] is the initial reactant concentration (unit: mol.L-1 or M)

k is the rate constant of the reaction (unit: M(1-n)s-1 where ‘n’ is the reaction order)