When the solid A is added to water, it dissolves with the evolution of a lot of heat and making little explosions to form two products B and C. The properties of products B and C are entirely different from those of solid A as well as water. Moreover, products B and C cannot be reconverted into solid A and water. When another solid D is added to water, it dissolves with the absorption of a little heat to form a product E which cools down. The product E shows the properties of both, solid D as well as water. Moreover, product E can be converted into solid D and water.
(a) What type of change occurs when solid A is dissolved in water? Why?
(b) What type of change occurs when sold D is dissolved in water? Why?
(c) Name a metal which you think could behave like solid A. Also name the products B and C.
(d) Name the solid D if it is the one which is used in making ordinary dry cells.
(e) Name the process by which D can be recovered from E.
(a) Chemical change; Because the properties of products B and C are entirely different from those of solid A and water
(b) Physical change; Because the product E shows the properties of both, solid D and water
(c) Sodium; Sodium hydroxide and Hydrogen
(d) Ammonium chloride
(e) Evaporation