`DeltaH_("neutralisation")` is always

Options

A. positive
B. negative
C. zero
D. positive or negative

Answer

To determine the value of ΔH (delta H) for a neutralization reaction, we can follow these steps:

### Step 1: Understand the concept of ΔH
ΔH, or change in enthalpy, refers to the heat content change during a chemical reaction. It can be positive or negative depending on whether the reaction absorbs or releases heat.

**Hint:** Remember that ΔH is a measure of heat change in a reaction.

### Step 2: Identify the type of reaction
A neutralization reaction occurs when an acid reacts with a base to produce salt and water. This is a specific type of reaction that typically involves the transfer of protons (H⁺ ions) from the acid to the base.

**Hint:** Recall the general equation for a neutralization reaction: Acid + Base → Salt + Water.

### Step 3: Determine the heat exchange in neutralization
In a neutralization reaction, heat is released as the acid and base react. This release of heat indicates that the reaction is exothermic.

**Hint:** Exothermic reactions are characterized by the release of heat.

### Step 4: Relate heat release to ΔH
Since heat is released in an exothermic reaction, ΔH for the neutralization reaction will be negative. This means that the enthalpy of the products is lower than that of the reactants.

**Hint:** Remember that negative ΔH indicates that the reaction releases energy.

### Step 5: Conclusion
Therefore, ΔH for neutralization reactions is always negative.

**Final Answer:** ΔH (neutralization) is always negative.