Question

Three beakers labelled as A, B and C each containing 25 mL of water were taken. A small amount of NaOH, anhydrous CuSO4 and NaCl were added to the beakers A, B and C respectively. It was observed that there was an increase in the temperature of the solutions contained in beakers A and B, whereas in case of beaker C, the temperature of the solution falls. Which one of the following statement(s) is(are) correct? (i) In beakers A and B, exothermic process has occurred.(ii) In beakers A and B, endothermic process has occurred.(iii) In beaker C exothermic process has occurred.(iv) In beaker C endothermic process has occurred. i only ii only i & iv ii & iii

Answer 1

Correct Option➡(C)

✔Chemical reaction in beakers A and B gives out heat.

✔Hence the temperature of the solution increases.

✔Thus, we can call it an exothermic reaction.

✔ In beaker C, heat is absorbed from water instead and hence the temperature decreases.

✔Thus, we can call it an endothermic process.

Answer 2

Answer:

• For an exothermic reaction, heat releases during reaction so temperature increases whereas endothermic reactions proceed with absorption of heat which decrease the temperature of reaction.
• The correct option is i&iv