Question

If the pressure in the reaction vessel for the following reaction is increased by decreasing the volume, what will happen to the concentration of $CO$ and $C {{O}_{2}}$?
   ${{H}_{2}}O+CO(g)\to {{H}_{2}}(g)+C{{O}_{2}}(g)+Heat$
A.Both the $\left[ CO \right]$ and $\left[ C{{O}_{2}} \right]$ will decrease
B.Neither $\left[ CO \right]$ nor $\left[ C{{O}_{2}} \right]$ will change
C.The $\left[ CO \right]$ will decrease and the $\left[ C{{O}_{2}} \right]$ will increase
D.Both the$\left[ CO \right]$and $\left[ C{{O}_{2}} \right]$ will increase

Answer 1

Hint:Concentration of a substance in a solution is defined as the amount of substance dissolved in the solution per unit-volume. If the volume of the solution decreases while the amount of the substance is kept constant, the concentration increases.

Complete answer:
The pressure in the reaction vessel is increased by decreasing the volume so since concentration is the amount of substance dissolved in the solution per unit volume so if volume is decreased then concentration will increase. Therefore, concentration of both $CO $and $C{{O}_{2}}$ will increase.

So, the correct option is (D).

Additional Information:
 Le Chatelier's principle is an observation about chemical equilibrium of reactions. It states that changes in the temperature, pressure, volume, or concentration of a system will result in predictable and opposing changes in the system in order to achieve a new equilibrium state. Le Chatelier's Principle helps to predict what effect a change in temperature, concentration or pressure will have on the position of the equilibrium in a chemical reaction.
Effect of pressure: Le Chatelier's principle implies that a pressure increase shifts the equilibrium to the side of the reaction with the fewer number of moles of gas, while a pressure decrease shifts the equilibrium to the side of the reaction with the greater number of moles of gas.
Effect of volume: When the volume increases, there are fewer molecules per unit volume. This means the number of collisions per unit of surface area decreases, so the pressure is lower. Effectively, increasing the pressure by decreasing the volume increases the concentration.

Note:
Other factors like changing the Temperature or increasing the concentrations of reactants and products can also affect the equilibrium state. If there had been an increase in the volume then concentration would have decreased. According to the ideal gas equation, pressure is directly proportional to concentration, assuming volume and temperature are constant.