Question

The salt solution obtained by dissolving a salt in a cup of water is kept in the sun for two days. The observation that will be made is-
A) the salt solution will remain as such
B) salt will evaporate, leaving water behind
C) neither salt nor water will remain
D) water will evaporate, leaving salt behind

Answer 1

Answer:

d water will evaporate , leaving the salt behind

Answer 2

The observation that will be made is - water will evaporate, leaving salt behind. (Option D)

• When the salt solution (water + salt) was kept in the sun, it is actually exposed to significant amount of heat energy application.
• Now, we know that, water has a tendency of evaporation (conversion from liquid to gas). During this two days long time interval of heat energy application, the water gets enough amount of time (as evaporation is a slow process) and heat energy, to get completely evaporated.
• On the other hand, salt (solid substance) has no such tendency of evaporation. That's why, after water evaporation is completed, the remaining salt stays behind without any noticeable change.
• Hence, the observation will be - water will evaporate, leaving salt behind.