For a hypothetical reaction of kind.
`AB_(2)(g)+1/2 B_(2)(g) hArr AB_(3)(g), DeltaH=-x kJ`
More `AB_(3)` could be produceed at equilibrium by

Options

A. Using a catalyst
B. Removing some of `B_(2)`
C. Increasing the temperature
D. Increasing the pressure

Explanation

To determine how more \( AB_3 \) could be produced at equilibrium for the reaction:

\[ AB_2(g) + \frac{1}{2} B_2(g) \rightleftharpoons AB_3(g), \quad \Delta H = -x \, \text{kJ} \]

we need to analyze the effects of various changes according to Le Chatelier's principle and the characteristics of the reaction.

### Step-by-Step Solution:

1. **Understanding the Reaction**:
- The reaction involves the conversion of 1 mole of \( AB_2 \) and 0.5 moles of \( B_2 \) into 1 mole of \( AB_3 \).
- This means that there is a decrease in the total number of moles from 1.5 moles of reactants to 1 mole of product.

2. **Effect of Pressure**:
- According to Le Chatelier's principle, increasing the pressure will favor the side of the reaction that produces fewer moles of gas.
- Since the reactants (1.5 moles) produce fewer moles (1 mole of \( AB_3 \)), increasing the pressure will shift the equilibrium to the right, favoring the formation of \( AB_3 \).

3. **Effect of Temperature**:
- The reaction is exothermic (as indicated by \( \Delta H = -x \)).
- For exothermic reactions, lowering the temperature favors the formation of products. Therefore, decreasing the temperature will also shift the equilibrium to the right, producing more \( AB_3 \).

4. **Effect of Concentration**:
- Increasing the concentration of the reactants \( AB_2 \) or \( B_2 \) will shift the equilibrium to the right, favoring the formation of \( AB_3 \).
- This is because adding more reactants will increase the chances of them colliding and reacting to form products.

5. **Effect of a Catalyst**:
- A catalyst increases the rate of both the forward and reverse reactions equally and does not affect the position of equilibrium.
- While it does not change the amount of \( AB_3 \) produced at equilibrium, it allows the system to reach equilibrium faster.

6. **Effect of Removing Reactants**:
- Removing \( B_2 \) would decrease the concentration of reactants, which would shift the equilibrium to the left (favoring the formation of reactants), thus not favoring the production of \( AB_3 \).

7. **Effect of Increasing Temperature**:
- Increasing the temperature for an exothermic reaction would shift the equilibrium to the left, favoring the reactants and decreasing the production of \( AB_3 \).

### Conclusion:
To produce more \( AB_3 \) at equilibrium, one could:
- Increase the pressure.
- Decrease the temperature.
- Increase the concentration of \( AB_2 \) or \( B_2 \).