The following reaction is known to occur in the body `CO_(2) + H_(2)O hArr H_(2)CO_(3) hArr H^(+) + HCO_(3)^(-)`. If `CO_(2)` escapes from the system

Options

A. pH will decrease
B. Hydrogen ion concentration will decrease
C. `H_(2)CO_(3)` concentration will be unaltered
D. The forward reaction will be promoted

Explanation

To solve the problem, we need to analyze the given equilibrium reaction and apply Le Chatelier's principle to understand the effect of removing CO₂ from the system on the pH.

### Step-by-Step Solution:

1. **Write the Equilibrium Reaction**:
The reaction we are dealing with is:
\[ CO_2 + H_2O \rightleftharpoons H_2CO_3 \rightleftharpoons H^+ + HCO_3^- \]
Here, carbon dioxide (CO₂) reacts with water (H₂O) to form carbonic acid (H₂CO₃), which can further dissociate into hydrogen ions (H⁺) and bicarbonate ions (HCO₃⁻).

2. **Identify the Change in the System**:
The problem states that CO₂ escapes from the system. This means the concentration of CO₂ is decreasing.

3. **Apply Le Chatelier's Principle**:
According to Le Chatelier's principle, if a system at equilibrium is subjected to a change in concentration, pressure, or temperature, the system will adjust to counteract that change and restore a new equilibrium. In this case, since CO₂ is a reactant, its removal will shift the equilibrium to the left (backward direction) to produce more CO₂.

4. **Determine the Effect on H₂CO₃ and H⁺ Concentrations**:
- As the equilibrium shifts to the left, the concentration of carbonic acid (H₂CO₃) will decrease.
- Since H₂CO₃ can dissociate into H⁺ ions, a decrease in H₂CO₃ will lead to a decrease in the concentration of H⁺ ions.

5. **Conclude the Effect on pH**:
- The pH of a solution is inversely related to the concentration of H⁺ ions. Therefore, if the concentration of H⁺ ions decreases, the pH will increase (the solution becomes less acidic or more basic).

### Final Answer:
- The pH of the solution will increase when CO₂ escapes from the system.