Three beakers labelled as A, B and C each containing 25 mL of water were taken. A small amount of NaOH, anhydrous `CuSO_(4)` 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 followig statement (s) is (are) correct?
1. In beakers A and B, exothermic process has occurred.
2. In beakers A and B, endothermic process has occurred.
3. In beaker C, exothermic process has occurred.
4. In beaker C, endothermic process has occurred.

Options

A. Only (i)
B. Only (ii)
C. (i) and (iv)
D. (ii) and (iii)

Answer

C

Explanation

In beakers A and B, exothermic reactions have occurred. Dissolution of NaOH and anhydrous `CuSO_(4)` are exothermic reactions, hence there is increase in temperature. Dissolution of NaCl results in decrease in temperature hence, endothermic reaction takes place in beaker C.