To Determine the Enthalpy of Neutralization of a Strong Acid(HCl) with a Sturdy Base (NaOH)

Material Required 

  • Beakers (250 mL)
  • Thermometer (110°C)
  • Glass rod, Cotton wool
  • Small wooden block
  • Piece of cardboard
  • Stirrer
  • Calorimeter
  • 1M HCl (100 mL)
  • 1M NaOH (100 mL) 


The Procedure 

Real Lab Procedure 

  • Determination of Enthalpy of Neutralization 
  • Calculate the calorimeter's water equivalent. 
  • Put 100mL of a 1M hydrochloric acid solution in it. 
  • Next, note the acid solution's temperature. 
  • Take another vessel and fill it with 100mL of 1M sodium hydroxide solution. 
  • Make a note of the sodium hydroxide's initial measurement's temperature. 
  • Note down the temperature of both the solutions, which are likely to be the same. Let it be t1°C. 
  • Now rapidly add 100mL of 1M sodium hydroxide solution to the hydrochloric acid. 
  • Put the cork in place right away. It contains a thermometer and a stirrer in the mouth. 
  • After brief intervals, take note of the temperature and stir the solution well. 
  • Till the temperature is steady, keep taking notes on it. 
  • Note the greatest temperature attained. 
  • Determine the heat released when the two solutions are combined using the ratio-proportion method.   

Simulation Procedure 

  • 100mL of 1M hydrochloric acid solution is dragged into a calorimeter. 
  • Drag a piece of cardboard that contains a thermometer and a stirrer into the mouth to close it. 
  • Note the temperature of acid solutions. 
  • Click on the 250mL beaker. 
  • 100mL of 1M sodium hydroxide solution is dragged 
  • Drag the thermometer into the beaker. 
  • Note the temperature of the NaOH solution. 
  • Take note of the initial temperature ‘ t1°C’. 
  • Click the thermometer to take it out of the beaker of NaOH. 
  • Click the cardboard to open it. 
  • Click and drag the 100mL of sodium hydroxide solution and drop it into the hydrochloric acid. 
  • Click and drag the cardboard to close. 
  • Click the stirrer to stir the solution well and note the final temperature of the mixture. Let it be t2°C. 



Initial temperature of the acid and base  t1°C 
Final temperature after neutralization  t2°C
Change in temperature Δt (t1-t2) °C
Mass of the mixture solution after neutralization 200g
Water equivalent of calorimeter Wg



Enthalpy change during neutralization of 100mL of 1.0M HCl  =  (200 × W) ×(t1 - t2) ×4.18 

When 1000 mL of 1M HCl is allowed to neutralize 1000 mL of 1M NaOH, calculate the heat that is released. This amount would be ten times greater than what was achieved. 

                                                                                                              =  (200×W) ×(t1−t2) ×4.18  x1000

                                                                                                                                   1.0                       100


       Enthalpy of neutralization                                                    =  (200×W) ×(t1−t2) ×4.18  KJ 

                                                                                                                             1.0 x 100



     Enthalpy change in neutralizing sodium hydroxide solution with hydrochloric acid solution is ______ kJmol-1. 



  • Some heat is lost to the environment because of radiation. 
  • The recommended solution density is 1g/ml. 
  • Ionization of sodium hydroxide and hydrochloric acid is taken to be 100%. 
  • The calculated specific heat of the solution is 4.189 J/g. 
  • The HCl and NaOH mixture must be well agitated. 
  • Accurate calculations should be made for the water equivalent calorimeter or beaker.