Question

Which of the following processes is/are endothermic?

	1.	the combustion of hydrogen
	2.	the condensation of water
	3.	the evaporation of isopropyl alcohol

	a.	1 only
	b.	2 only
	c.	3 only
	d.	1 and 3
	e.	1, 2, and 3

Answer 1

o combustion of hydrogen Exothermic} на <a) +о, с. — Но (1) дн«Нt; chara sa would be negative as reaction is taking place. ah= sha free, energy change OH-TAS . .. As = entropy change since, two gas molecules are converted into liquid. Hence, entropy change is negative. .., 04 = A + ltos! - tre quantity avě hn must be negative oh is negative and as is negative. Therefore, Oh must be regatire. 1. gf on is negatire , then process is exothermic. ③ [Condensation of water & Exothermic) C H₂O cg) condensation H₂O(l) . Gasean H₂O rapours are highly energetic. It will have to loose energy to conderse into liquid form which is lessen energetic. Therefore, this proces will be exothermic. & Endothermic | evaporation of isophropyl alcohol Alcoh (el eroporation Alcohol is Aleoed caly crta

Liquid molecules have lower energy since it's nove: -ment is restricted while, gaseous molecules are highly energetic and more rapidly. . Hence, external energy I heat would be required to convent alchool in liquid state into gaseous state. Therefore, evaporation would be endother -mic process. Anore Option ② is: correct re. 3 only /