Unit 5 Acid/base Equilibrium Quiz

K> > 1

Favorable reaction that is assumed to go to completion

K < < 1

Unfavorable reaction that will have a small amount of product while majority of reactants remain

Acids:

any substance that donates H+ to the solution

Bases:

any substance that accepts H+ in a solution, and indirectly increase OH concentration

How are acids classified?

By the number of H+ ions they donate

Monoprotic acids:

donate 1 H+ ion

Diprotic acids:

donate 2 H+ ions

Polyprotic acids:

donate many H+ ions

H+ donation occurs in _____ _____ steps and becomes ____ difficult due to acomidating electrons

separate steps; increasingly

Strong acids form _____ conjugate bases

weak

Strong bases form ____ conjugate acids

weak

Strong acids to know:

HCl, HBr, HNO3, H2SO4, and HCLO4

Assume acids other than this are week

Strong bases to know(general description):

highly soluble metal hydroxides(contain OH)

Examples: alkali metal hydroxides( KOH, NaOH, etc.)

Assume bases other than these are weak

What is considered very acidic based on the pH scale?

The lower the pH, the more acidic the solution is. The higher the pH, the more basic the solution is

What kind of pH will a strong acid have?

A very low pH

pH =

-log [H]

pOH =

-log [OH]

What pH does a neutral solution have?

pH = 7

Acidic solution in terms of pH and concentration of H+:

[H] > 1 × 10^-7

pH<7

Basic solution in terms of pH and concentration of H+ :

[H] < 1 × 10^-7

pH > 7

pKa =

-log Ka

pKb =

-log Kb

What does HA represent?

the acid in the solution(can donate the H, leaving only A)

What does A represent?

The conjugate base

How are conjugate pairs related?(what is the value of this?)

They are related by Kw(The K of the dissociation of water)

Kw = 1×10^-14

What defines a weak conjugate?

to be less reactive than water

What defines a strong conjugate?

to be more reactive than water

What is must the acids and conjugates be in terms of strength for hydrolysis to occur?

The acid/base must be weak, making the conjugate acid/base strong, which results in a reaction called a hydrolysis reaction

What is the result of a hydrolysis reaction?

It effects the overall pH

What must you be careful with when calculating pH of reactions that result in a hydrolysis reaction?

You must use the correct K value(Ka or Kb) based on if there is a weak acid or base present

What determines if a substance can donate/accept H+ ions?

Its structure; bases must have location and electrons for H+ to attach to

What atoms accommodate electrons more easily?

More electronegative atoms

When is equilibrium(Keq) established?

When the rate of the forward process is equal to the rate of the reverse reaction

What are all 6 of the strong acids?

HCl, HBr, HI, HNO3, H2SO4, HClO4

K forward =

1/K reverse

If K >> 1 and M is the molarity of the starting substance(acid or base), whst is the concentration of the products

Each product will have a concentration of M as the reaction is highly favorable and is therefore assumed to go to completion

Ka * Kb =

[H3O+] * [OH-]

How do you identify conjugate when there are no acids/bases present?

Break the equation into separate equations, one for each reactant to show what each is being broken in to. Then identify if there are any strong conjugate present

How do you determine the effect a strong conjugate has on the reaction?

If it is a strong conjugate base, it will increase pH as it results in the formation of OH, lowering the acidity

If it is a strong conjugate acid, it will decrease pH as it will result in the formation of H, increasing the acidity