Answer:
B) Add appropriate quantities of weak acid and its conjugate base to water.
C) Partially neutralize a weak acid solution by addition of a strong base.
(D) Partially neutralize a weak base solution by addition of a strong acid.
Explanation:
A buffer solution is made by a weak acid and its conjugated base or a weak base and its conjugated acid.
If you add a weak acid to water, you can adjust the pH of the buffer solution by adding a strong base.
If ypu add a weak base to water, you can adjust the pH of the buffer solution by adding a strong acid.
1.25 g x 22.4 l / 1 mol = 28 g/mol
Answer:
The options are unclear, however, the correct option is:
Aqueous solutions of ionic compounds cause to dissociate, hence, ions are free to conduct electricity
Explanation:
Ionic compounds are compounds formed from ions (charged atoms). For example, NaCl is an ionic compound from the following ions; Na+ (cation) and Cl- (anion). One characteristics of ionic compounds is their ability to dissociate into the ions that form them when in an aqueous solution i.e. NaCl will dissociate into Na+ and Cl- when in an aqueous solution.
These disssociated ions are free to conduct electricity, hence, making ionic compounds good conductors of electricity.
Question #1
Potasium hydroxide (known)
volume used is 25 ml
Molarity (concentration) = 0.150 M
Moles of KOH used
0.150 × 25/1000 = 0.00375 moles
Sulfuric acid (H2SO4)
volume used = 15.0 ml
unknown concentration
The equation for the reaction is
2KOH (aq)+ H2SO4(aq) = K2SO4(aq) + 2H2O(l)
Thus, the Mole ratio of KOH to H2SO4 is 2:1
Therefore, moles of H2SO4 used will be;
0.00375 × 1/2 = 0.001875 moles
Acid (sulfuric acid) concentration
0.001875 moles × 1000/15
= 0.125 M
Question #2
Hydrogen bromide (acid)
Volume used = 30 ml
Concentration is 0.250 M
Moles of HBr used;
0.25 × 30/1000
= 0.0075 moles
Sodium Hydroxide (base)
Volume used 20 ml
Concentration (unknown)
The equation for the reaction is
NaOH + HBr = NaBr + H2O
The mole ratio of NaOH : HBr is 1 : 1
Therefore, moles of NaOH used;
= 0.0075 moles
NaOH concentration will be
= 0.0075 moles × 1000/20
= 0.375 M
