# Some Equilibrium Problems

1. Apr 28, 2005

### Artermis

1. Which of the following salts act like acids when applied to soil?

a. $$BeCl_2$$
b. $$KF$$
c. $$FeI_3$$
d. $$LiNO_3$$
e. $$KClO_4$$

I believe the answer is c, any confirmation?

2. Which of the following salts act like bases when applied to the soil?

a. $$NaHSO_4$$
b. $$KNO_2$$
c. $$CaCl_2$$
d. $$LiNO_3$$
e. $$KClO_4$$

I believe the answer is b, and either a or b, but again, my reasoning is not solid =( would appreciate an explanation

3. All of the following are strong electrolytes in aqueous solution EXCEPT:
a. acetic acid (HC2H3O2)
b. sodium acetate (NaC2H3O2)
c. ammonium acetate (NH4HC2H3O2)
d. sodium hydroxide (NaOH)
e. hydrochloric acid (HCl)

I'm pretty sure the answer is either a or b. I understand that electrolyte means strong dissociation in water; with positive and negative ions that are able to conduct electricity. (Same thing like the self-ionization of water, where it ionizes very slightly into positive hydronium ions and negative hydroxide ions) I know that acetic acid is a relatively weak acid, and sodium acetate dissociates... I guess, but does Na+ being neutral have anything to do with it? I'd have to go down to a hunch and say acetic acid because it's a weak acid.

4. Which solution has the highest pH?

a. 0.1 M Hydrochloric acid
b. 0.1 M $$NH_3$$
c. 0.1 M $$Na_2NO_2$$
d. 0.1 M $$AlCl_3$$
e. 0.1 M $$CH_3COOH$$

I'm sure that the answer is either b or c. I'm looking for the least acidic, and most basic compound. I think it is c because when it breaks up into ions, the NO2 has a more negative charge, not sure if this is correct: Na^2+ and 2NO2- so therefore it c will want to draw H protons to itself because of its - charge.

5. The value of $$K_w$$ increases as the temperature of water is raised. What effect will increasing the temperature have on its pH?

I'm kind of stumped on this one. I know that increasing the temperature will increase the value of Kw. (side note: why, exactly?) but do the concentrations of H+ and OH- grow equally? I'm thinking it either lowers the pH (more acidic) or stays the same. I'm really not sure about this one and I'm worried because I can't figure it out. =(

That's all for now, I'm sorry if these questions seem trivial to you, but I really tried to think them through!

-Art

Last edited: Apr 28, 2005