Question

Ag- Ap E T D-A BEE - AaBbCcD AaBbCcD AaBbC AaBbCc A T Normal Heading 1 Heading 2 No Spac... Tn Paragraph Styles 15. How are molecular and ionic solutes different in the way they affect bolling points of solutions? 16. How is the freezing point of a solution different from the freezing point of a pure substance? Why? 17. What are the 3 classes of electrolytes? Of bases. 18. List 4 properties of acids. 19. What are the differences between strong and weak acids and bases? 20. What does the pH measure? What is the range for acids? For bases? 21. What are the procerties of salts? a

Answer 1

15. The elevation of boiling point can be given by

AT= To,solution - To, solvent = i.k.Cm

k_b is constant, C is molality of the solution, and i is the van 't Hoff factor.

For molecular (non-ionic) solute, i=1

For ionic solute, i>1.

So, the presence of ionic solute raises the boiling point.

16. The freezing point of the solution will be lowered compared to a pure substance (according to freezing point depression).

17. (i) strong electrolyte

strong acid, e.g: HCl

strong base, e.g: NaOH

salt, e.g: NaCl

(ii) weak electrolyte

weak acid, e.g: H₂CO₃

weak base, e.g: NH₃

(iii) Non-electrolyte

sugar, fats, etc.

18. Properties of acids:

i. It gives H₃O⁺ ion in water or it is a lone-pair acceptor (Lewis acid). Mostly electrolyte in aqueous solution.

ii. forms salt by reacting with a base.

iii. releases hydrogen gas while reacting with the metal.

iv. changes the color of a p^H indicator.

v. taste: sour

Properties of bases:

i. It gives OH^- ion in water or it is a lone-pair donar (Lewis base).

ii. forms salt by reacting with acid.

iii. taste: bitter.

iv. it conducts electricity.

19. Strong acid or base is fully dissociated in an aqueous solution.

e.g: HCl+H₂O ----> H₃O⁺ +Cl^-

Weak acid or base is partially dissociated.

20. p^H=-log₁₀[ H₃O⁺]

For acid: p^H: 0-7

For base: p^H: 7-14

21. Properties of salts:

i. ionic in nature.

ii. mostly water-soluble.

iii. usually insulator. But in an aqueous medium, it carries charges.

iv. mostly, salty in taste.

v. it has a high melting point.