Which of the following concepts is (are) wrong?

Options

A. If for, `AtoB" "DeltaH=+q` cal
then for, `BtoA" "DeltaH=-q` cal
B. If for, `AhArrB` eqb. Constant = K
then for, `BhArrA` eqb. Constant = `1/K`
C. If for, `AtoB` rate constant = k
then for, `BtoA` rate constant `nek`
D. If for, `AtoB` energy of activation = E
then for, `BtoA` energy of activation = -E.

Answer

To determine which of the concepts presented in the question is wrong, we will analyze each statement step by step.

### Step 1: Analyze the First Statement
The first statement discusses the enthalpy change (ΔH) of a reaction and states that if you reverse the reaction, the heat becomes negative.

**Analysis:**
- When a reaction is reversed, the sign of ΔH changes. If the forward reaction has ΔH = q, then the reverse reaction will have ΔH = -q.
- **Conclusion:** This statement is correct.

### Step 2: Analyze the Second Statement
The second statement refers to the equilibrium constant (K) of a reaction. It states that if you reverse the reaction, the equilibrium constant becomes 1/K.

**Analysis:**
- For a reaction A ⇌ B, the equilibrium constant K is defined as K = [B]/[A].
- If the reaction is reversed (B ⇌ A), the new equilibrium constant K' will be K' = [A]/[B] = 1/K.
- **Conclusion:** This statement is correct.

### Step 3: Analyze the Third Statement
The third statement discusses the rate constant (k) of a reaction. It states that if you reverse the reaction, the rate constant will not be equal to k.

**Analysis:**
- The rate constant for the forward reaction (A → B) is k. For the reverse reaction (B → A), the rate constant is k'. The relationship between k and k' is given by k' = k * ([A]/[B]), which is not necessarily equal to k.
- **Conclusion:** This statement is correct.

### Step 4: Analyze the Fourth Statement
The fourth statement discusses activation energy (Ea) and claims that if you go from B to A, the value of Ea will be -E.

**Analysis:**
- Activation energy is the energy required to initiate a reaction. It is always a positive value. The statement that Ea from B to A is equal to -E is incorrect because activation energy cannot be negative.
- **Conclusion:** This statement is incorrect.

### Final Conclusion
The fourth statement is the only incorrect concept among the options provided.