Answer is: by increasing the temperature of the solvent.
Saturated solution contains the maximum concentration of a solute dissolved in the solvent (usually water) and if extra solute is add to saturated solution, that solute will not dissolve.
The amount of solute that can be dissolved in a solvent depends of chemical composition, temperature and pressure.
In this example, because chemical compostion and pressure are the same, the amount of solute that can be dissolved in a solvent depends on temperature.
The higher the temperature of the solvent, the more solute will be dissolved.
The graph shown the potential energy diagram of the reaction "reaction pathway".
X-axis represents the reaction progress, the transformation from the reactants to the products passing via the transition state.
Y-axis represents the potential energy of the reactants and the products and also the intermediate.
As clear from the attached image "F" represents the position of the reactants of the reaction, "B" represents the position of the intermediate/transition state and "G" represents the position of the products of the reaction.
Region "A" is the potential energy difference between the intermediate "B" and the reactants "F" which represents the activation energy of the reaction "Ea". Activation energy "Ea" can be defined as the minimum energy that the reactants should posses to initiate the reaction.
Region "C" is the potential energy difference between the reactants "F" and the products "G" which represents the enthalpy change of the reaction "ΔH".
<em>ΔH = pot. energy of the products "G" - pot. energy of the reactants "F".</em>
If "ΔH" is positive this means that the reaction is endothermic and this occurs when the potential energy of the products is greater than that of the reactants.
If "ΔH" is negative this means that the reaction is exothermic and this occurs when the potential energy of the products is smaller than that of the reactants.
In our example, It is obvious that the energy of the reactants is greater than the potential energy of the products.
So, ΔH will have a negative value which means that the reaction is exothermic reaction.
<em>Thus, the right choice is: "subtract E from D" would provide evidence to support the inference that this is an exothermic reaction.</em>
So, if 1 mole occupies 22.4 L, the imediate conclusion is that a bigger number of moles will occupy more than 22.4 L, and a smaller number of moles will occupy less than 22.4 L. In your case, 3 moles of gas will occupy 3 times more volume than 1 mole of gas