The order of reaction is an experimentally determined quanity. It may be zero, poistive, negative, or fractional. The kinetic equation of `nth` order reaction is
`k xx t = (1)/((n-1))[(1)/((a-x)^(n-1)) - (1)/(a^(n-1))]` …(i)
Half life of `nth` order reaction depends on the initial concentration according to the following relation:
`t_(1//2) prop (1)/(a^(n-1))` ...(ii)
The unit of the rate constant varies with the order but general relation for the unit of `nth` order reaction is
Units of `k = [(1)/(Conc)]^(n-1) xx "Time"^(-1)` ...(iii)
The differential rate law for `nth` order reaction may be given as:
`(dx)/(dt) = k[A]^(n)` ...(iv)
where `A` denotes the reactant.
For a reaction:
`I^(ɵ) + OCl^(ɵ) rarr IO^(ɵ) + Cl^(ɵ)`
in an aqueous medium, the rate of the reaction is given by
`(d[IO^(ɵ)])/(dt) = k([I^(ɵ)][OCl^(ɵ)])/([overset(ɵ)(OH)])`
The overall order of the reaction is

Options

A. `-1`
B. `1`
C. Zero
D. `2`

Explanation

To determine the overall order of the reaction given by the rate law:

\[ \frac{d[IO^-]}{dt} = k \frac{[I^-][OCl^-]}{[OH^-]} \]

we'll follow these steps:

### Step 1: Identify the concentrations in the rate law
The rate law provided indicates the concentrations of the reactants and products involved in the reaction. Here, we have:
- \([I^-]\) (iodine)
- \([OCl^-]\) (hypochlorite)
- \([OH^-]\) (hydroxide ion)

### Step 2: Determine the order with respect to each reactant
In the rate law, the concentration of each reactant is raised to a power that indicates its order in the reaction:
- The concentration of \([I^-]\) is raised to the power of 1 (order = +1).
- The concentration of \([OCl^-]\) is also raised to the power of 1 (order = +1).
- The concentration of \([OH^-]\) is in the denominator, which indicates a negative order (order = -1).

### Step 3: Calculate the overall order of the reaction
The overall order of the reaction is the sum of the individual orders with respect to each reactant:
\[ \text{Overall Order} = \text{Order of } [I^-] + \text{Order of } [OCl^-] + \text{Order of } [OH^-] \]
Substituting the values:
\[ \text{Overall Order} = (+1) + (+1) + (-1) = 1 \]

### Conclusion
The overall order of the reaction is **1**.

---