Experiment 16: Heat generation during reaction


  • To measure the change in temperature during chemical reactions and to conclude whether the reaction is exothermic or endothermic

Materials required:

  • Dil Sodium hydroxide solution
  • Dil hydrochloric acid,
  • ammonium chloride (solid)
  • barium hydroxide (solid)
  • four test tubes
  • thermometer (–10 ºC to 110 ºC)


  • Mark all the four clean test tubes as 1, 2, 3, and 4.
  • Take 5 mL of sodium hydroxide solution in test tube no. 1; 5 mL of hydrochloric acid in test tube no. 2
  • Add 1g of barium hydroxide with 5ml of water in # 3, and 1g of ammonium chloride with 5ml of water in #4
  • Record temperatures of each TT
  • Pour the contents of TT no. 1 in TT no. 2 and record the final temperature reading of the thermometer
  • Pour the contents of TT no. 3 in TT no. 4. and record the final temperature readings of the thermometer



Initial T (T1)
Final T (T2)
Change (T2-T1)
NaOH + HCl
Ba(OH) 2.8H2O + 2NH4Cl


  • The reaction between sodium hydroxide solution and hydrochloride acid is exothermic
  • Reaction between barium hydroxide solution and ammonium chloride is endothermic.


  • The chemical reactions in which energy is absorbed are called endothermic reactions and those in which energy is released are known as exothermic reactions.