Rupali, a class `10` student has set up the apparatus as shown in the figures.

Which of the following observations is correct ?

Options

A. Temperature of beakers I, II and Ill will be raised as dissolution of salts is an exothermic process.
B. Temperature of beakers III and IV will be raised while temperature of beakers I and Il will fall.
C. Temperature will rise only in beaker IV as redox reactions are exothermic.
D. None of these

Answer

B

Explanation

Dissolution of salts may be endothermic or exothermic but displacement reactions are always exothermic. Dissolution of `K_2SO_4` and `NH_4NO_3` in water is an endothermic process and hence temperature will fall in beakers I and II. Dissolution of anhy. `CuSO_4` and displacement reaction between Zn and `CuSO_4` both are exothermic reactions and hence temperature will rise in beakers III and IV.