To calculate the standard enthalpy change H for the reaction, we first need to determine the heat released or absorbed during the reaction q . We can do this using the formula:q = mcTwhere m is the mass of the solution, c is the specific heat capacity, and T is the change in temperature.Since the density of the solutions is 1.00 g/mL, the mass of each solution can be calculated as follows:mass = volume densitymass = 50.0 mL 1.00 g/mL = 50.0 gThe total mass of the solution after mixing is the sum of the masses of the two solutions:total mass = mass of HCl solution + mass of NaOH solutiontotal mass = 50.0 g + 50.0 g = 100.0 gNext, we need to determine the change in temperature T during the reaction. The reaction between hydrochloric acid and sodium hydroxide is exothermic, meaning it releases heat. The heat released causes the temperature of the solution to increase. The change in temperature can be determined experimentally by measuring the initial and final temperatures of the solution and subtracting the initial temperature from the final temperature.T = T_final - T_initialAssuming you have the initial and final temperatures, you can now calculate the heat released q using the formula:q = mcTq = 100.0 g 4.18 J/gC T Now, we can determine the moles of the limiting reactant. Since both hydrochloric acid and sodium hydroxide have the same concentration and volume, they will react in a 1:1 ratio:moles of HCl = 2.0 mol/L 0.050 L = 0.100 molmoles of NaOH = 2.0 mol/L 0.050 L = 0.100 molSince both reactants have the same number of moles, neither is the limiting reactant, and they will both be completely consumed in the reaction.Finally, we can calculate the standard enthalpy change H for the reaction by dividing the heat released q by the moles of the limiting reactant:H = q / moles of limiting reactantH = q / 0.100 molPlug in the value of q you calculated earlier to find the standard enthalpy change H for the reaction.