Question

Which one of the following on mixing with water will result in rise of temperature?

(a) Sodium chloride
(b) Potassium nitrate
(c) Hydrated copper sulphate
(d) Sodium hydroxide ​

Answer 1

the answers will be , sodium hydroxide

Answer 2

Answer:

(a) Sodium chloride, when mixed in water increases the temperature of the solution.

Explanation:

• The mixing or dissolution of Sodium chloride in water is an endothermic reaction, i.e. when it takes place it increases the temperature of the solution by absorption of heat resulting in increase in temperature of the reaction mixture which increases the solubility of sodium chloride.

• Endothermic reactions are those that require additional energy to continue. The external energy is frequently present as heat. Endothermic processes tend to draw heat from their surroundings, which causes their environs to chill.
• Endothermic reactions are typically not spontaneous because the products they produce have higher energies than the reactants.
• Enthalpy changes for endothermic reactions are usually positive. In an endothermic reaction, the energy of the products is higher than the energy of the reactants.
• As a result  of the favourable enthalpy shift, the reaction draws heat from the environment. In such reactions, heat is drawn from the atmosphere, keeping the system where the reaction takes place colder.
• Additionally, the enthalpy, which is the difference in heat energy throughout the transfer of reactants to products, increases after the conclusion of the reaction.