Which of the follwing statement is not correct for the reaction,
`4A+Brarr2C+2D?`

Options

A. The rate of disappearance of B is one - fourth of the of disappearance of A
B. The rate of appearance of C is two times the rate of disappearance of B
C. The rate of formation of D is half the rate of consumption of A
D. The rates of formation of C and D are not equal

Answer

To solve the problem, we need to analyze the given reaction and the statements about it. The reaction is:

\[ 4A + B \rightarrow 2C + 2D \]

We will evaluate each statement to determine which one is not correct.

### Step 1: Write the Rate of Reaction
For the reaction, the rate of reaction can be expressed in terms of the change in concentration of reactants and products. The rate can be defined as:

\[ R = -\frac{1}{4} \frac{d[A]}{dt} = -\frac{d[B]}{dt} = \frac{1}{2} \frac{d[C]}{dt} = \frac{1}{2} \frac{d[D]}{dt} \]

### Step 2: Analyze Each Statement

#### Statement 1: The rate of disappearance of B is one fourth of the disappearance of A.
- The rate of disappearance of B is given by \(-\frac{d[B]}{dt}\).
- The rate of disappearance of A is given by \(-\frac{1}{4} \frac{d[A]}{dt}\).
- From the rate equations, we have:
\[ -\frac{d[B]}{dt} = \frac{1}{4} \left(-\frac{d[A]}{dt}\right) \]
- This means that the rate of disappearance of B is indeed one fourth of the rate of disappearance of A. **This statement is correct.**

#### Statement 2: The rate of appearance of C is 2 times the rate of disappearance of B.
- The rate of appearance of C is given by \(\frac{1}{2} \frac{d[C]}{dt}\).
- The rate of disappearance of B is given by \(-\frac{d[B]}{dt}\).
- From the rate equations, we have:
\[ \frac{1}{2} \frac{d[C]}{dt} = -\frac{d[B]}{dt} \]
- Rearranging gives:
\[ \frac{d[C]}{dt} = -2 \frac{d[B]}{dt} \]
- This means the rate of appearance of C is 2 times the rate of disappearance of B. **This statement is correct.**

#### Statement 3: The rate of formation of D is half the rate of consumption of A.
- The rate of formation of D is given by \(\frac{1}{2} \frac{d[D]}{dt}\).
- The rate of consumption of A is given by \(-\frac{1}{4} \frac{d[A]}{dt}\).
- From the rate equations, we have:
\[ \frac{1}{2} \frac{d[D]}{dt} = \frac{1}{4} \left(-\frac{d[A]}{dt}\right) \]
- This means the rate of formation of D is indeed half the rate of consumption of A. **This statement is correct.**

#### Statement 4: The rates of formation of C and D are not equal.
- The rate of formation of C is given by \(\frac{1}{2} \frac{d[C]}{dt}\).
- The rate of formation of D is given by \(\frac{1}{2} \frac{d[D]}{dt}\).
- From the rate equations, we have:
\[ \frac{1}{2} \frac{d[C]}{dt} = \frac{1}{2} \frac{d[D]}{dt} \]
- This means the rates of formation of C and D are equal. **This statement is not correct.**

### Conclusion
The statement that is not correct is:

**Option 4: The rates of formation of C and D are not equal.**