A quantity of 2.00 × 102 mL of 0.662 M HCl is mixed with 2.00 × 102 mL of 0.331 M Ba(OH)2 in a constant-pressure calorimeter of negligible heat capacity. The initial temperature of the HCl and Ba(OH)2 solutions is the same at 22.00°C. For the process below, the heat of neutralization is −56.2 kJ/mol. What is the final temperature of the mixed solutions? H+(aq) + OH−(aq) → H2O(l)

Final temperature of the solution = 26.43°C

Explanation:

Concentration of HCl = 0.662 M, Volume = 200 mL= 0.200 L

Concentration of Ba(OH)₂ = 0.331 M, Volume = 200 mL = 0.200 L

Initial temperature of solution = 22.00°C

Specific Heat capacity of water = 4.184 J/g°C

Heat of neutralization = -56.3 KJ/mol of H₂O produced.

The full calculations is found in the attachment below

the ideal gas law equation is as follows

pv = nrt

where p - pressure

v - volume

n - number of moles

r - universal gas constant

t - temperature

so if the pressure, volume and temperature are already known

we are left with n and r

since r is the universal gas constant that has a known fixed value then r too is known

so we are left with 'n'

once we know temperature volume and pressure

we can find the number of moles of gas present using the ideal gas law equation

this is not my own answer, this is an answer for the same question by the user blahblahmali. i do not claim ownership of this account.