The correct answer is Only 2. Key Points A neutralization reaction occurs when a solution of an acid is mixed with a solution of a base in a test tube. The result of the reaction is the production of salt and water with the evolution of heat. So temperature of the solution increases. NaOH (strong base) + HCl (strong acid) → ​NaCl (salt) + H2O CH3COOH + KOH → CH3COOK +H2O Hence 2 and 4 is the correct answer. Additional Information When a strong base and a weak acid reacts, the resultant is a solution with pH greater than 7, that is, basic. When a strong acid reacts with a weak base, the resultant solution has a pH lesser than 7, and the solution is acidic. When both are strong, the resultant solution is neutral. Whatever may be the case, the ultimate combination is the combination of a proton and a hydroxyl ion to give water.