False statement among these is:

Options

A. Rate of a zero order reaction is indepenent of initial concentration of reactant
B. Half life of a third order reaction is inversely proportional to the square of the initial concentration of the reactant
C. For a first order reaction `t_(1//2)=0.693/k`
D. Molecularity of a reaction may be zero, negative or even fractional

Answer

To determine the false statement among the given options regarding chemical kinetics, let's analyze each statement step by step:

### Step 1: Analyze the first statement
**Statement:** "The rate of a zero-order reaction is independent of the initial concentration of the reactant."

**Explanation:** For a zero-order reaction, the rate law is given by:
\[ \text{Rate} = k \]
This means that the rate is constant and does not depend on the concentration of the reactant. Therefore, this statement is **true**.

### Step 2: Analyze the second statement
**Statement:** "The half-life of a third-order reaction is inversely proportional to the square of the initial concentration of the reactant."

**Explanation:** The half-life for a reaction of order \( n \) is given by:
\[ t_{1/2} = \frac{1}{k[A_0]^{n-1}} \]
For a third-order reaction (\( n = 3 \)):
\[ t_{1/2} \propto \frac{1}{[A_0]^2} \]
This means that the half-life is indeed inversely proportional to the square of the initial concentration. Therefore, this statement is **true**.

### Step 3: Analyze the third statement
**Statement:** "For a first-order reaction, \( t_{1/2} = \frac{0.693}{k} \)."

**Explanation:** This is a well-known formula for the half-life of a first-order reaction. Therefore, this statement is **true**.

### Step 4: Analyze the fourth statement
**Statement:** "Molecularity of the reaction may be 0, negative, or even fractional."

**Explanation:** Molecularity refers to the number of reactant molecules that collide to produce a reaction. It can only be a positive integer (1, 2, 3, etc.). It cannot be 0, negative, or fractional. Therefore, this statement is **false**.

### Conclusion
The false statement among the options is:
**Option 4:** "Molecularity of the reaction may be 0, negative, or even fractional."

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