For the reaction
`4A +B rarr 2C+2D` which of the following statements is not correct:

Options

A. Rate of dissapearance of B is `1//4` th of rate of dissappearance of A
B. Rate of formation of C is `1//2` the rate of consumption of A
C. Rate of apperance of D is `1//2` the rate of dissappearance of B
D. Rate of formation of C and D are equal

Explanation

To determine which statement is not correct for the reaction \(4A + B \rightarrow 2C + 2D\), we will analyze the rates of disappearance and appearance of the reactants and products involved in the reaction.

### Step-by-Step Solution:

1. **Identify the Reaction Stoichiometry**:
The balanced equation is:
\[ 4A + B \rightarrow 2C + 2D \]
From this equation, we can see the stoichiometric coefficients: 4 for A, 1 for B, 2 for C, and 2 for D.

2. **Write the Rate Expressions**:
The rate of the reaction can be expressed in terms of the change in concentration of the reactants and products:
- Rate of disappearance of A:
\[ -\frac{1}{4} \frac{d[A]}{dt} \]
- Rate of disappearance of B:
\[ -\frac{1}{1} \frac{d[B]}{dt} \]
- Rate of appearance of C:
\[ \frac{1}{2} \frac{d[C]}{dt} \]
- Rate of appearance of D:
\[ \frac{1}{2} \frac{d[D]}{dt} \]

3. **Analyze Each Statement**:
- **Statement 1**: "The rate of disappearance of B is \( \frac{1}{4} \) the rate of appearance of A."
- This statement is **correct** because the rate of disappearance of B is indeed \( \frac{1}{4} \) of the rate of disappearance of A based on their stoichiometric coefficients.

- **Statement 2**: "The rate of formation of C is \( \frac{1}{2} \) the rate of consumption of A."
- This statement is also **correct** because the rate of formation of C is \( \frac{1}{2} \) the rate of consumption of A based on their stoichiometric coefficients.

- **Statement 3**: "The rate of appearance of B is \( \frac{1}{2} \) the rate of disappearance of B."
- This statement is **incorrect**. The rate of appearance of B cannot be compared to its own rate of disappearance in this way. The appearance of B is not applicable since B is a reactant and is consumed, not produced.

- **Statement 4**: "The rate of formation of C and D are equal."
- This statement is **correct** because both C and D are produced in equal amounts (2 moles each) according to the balanced equation.

4. **Conclusion**:
The statement that is not correct is **Statement 3**.