Trivia,Clicker Question Practice,

Conjugate Pairs,Indicator Dye Usage

http://drschrempp.com/Tests/Prep%20Chem/acid_base_practice_test.htmUC Davis ChemWiki

Trivia

• Acids taste sour and turn litmus paper red.• Bases taste bitter, feel slippery, and turn litmus

paper blue.• Amphoteric substances can act as both acids

and bases!

Trivia

• Sulfuric acid is manufactured in the largest quantities.

• Phosphuric acid is used in fertilizers, detergents, and as a flavoring in beverages.

• Nitric acid is used mainly in the manufacture of explosives, rubber, plastics, dyes, and drugs.

• Hydrochloric acid is produced in the stomach while bile is produced in the liver and stored in the gall bladder.

What is the molarity of an HCl solution if 50.0 mL is neutralized in a titration by 40.0 mL of 0.400 M NaOH?

1) 2) 3) 4) 5)

20% 20% 20%20%20%1) 0.200 M2) 0.320 M3) 0.280 M4) 0.500 M5) None of the above

What is the molarity of an HCl solution if 125 mL is neutralized in a titration by 76.0 mL of 1.22 M KOH?

1) 2) 3) 4) 5)

20% 20% 20%20%20%1) 0.371 M2) 0.617 M3) 0.455 M4) 0.742 M5) None of the above

What is the molarity of an NaOH solution if 4.37 mL is titrated by 11.1 mL of 0.0904 M HNO3?

1) 2) 3) 4) 5)

20% 20% 20%20%20%1) 0.230 M2) 0.460 M3) 0.355 M4) 0.620 M5) None of the above

Which of the following is perchloric acid?

1) 2) 3) 4) 5)

20% 20% 20%20%20%1) HClO2) HClO3

3) HClO2

4) HClO4

5) None of the above

Which of the following is chloric acid?

1) 2) 3) 4) 5)

20% 20% 20%20%20%1) HClO2) HClO3

3) HClO2

4) HClO4

5) None of the above

What unknown quantity can be calculated after performing a titration?

1) 2) 3) 4) 5)

20% 20% 20%20%20%1) Mass2) Volume3) Concentration4) Density5) None of the above

Which quantity is directly measured in a titration?

1) 2) 3) 4) 5)

20% 20% 20%20%20%1) Mass2) Volume3) Concentration4) Density5) None of the above

Which of the following bases is the WEAKEST? The base is followed by its Kb value.

1) 2) 3) 4) 5)

20% 20% 20%20%20%

Also, create stick diagrams for the organic molecules in answer choices 1 and 2.

1) (CH3CH2)3N 5.2 × 10-42) HOCH2CH2NH2 3.2 × 10-53) NH3 1.8 × 10-54) C5H5N 1.7 × 10-95) CN- 2.0 × 10-1

Conjugate Pair Examples

Equation Acid Base Conjugate Base

Conjugate Acid

HClO2 H2O ClO2- H3O+

H2O OCl- OH- HOCl

HCl H2PO4- Cl- H3PO4

Equation Acid Base Conjugate Base

Conjugate Acid

HF + H2O F- + H3O+

HSO4-+NH3 SO4

2-+NH4+

C2H3O2-+HCl HC2H3O2+Cl-

HNO2+ H2O H3O++ NO2-

HCN+ H2O H3O++ CN-

Conjugate Pair Practice

Equation Acid Base Conjugate Base

Conjugate Acid

HF + H2O F- + H3O+ HF H2O F- H3O+

HSO4-+NH3 SO4

2-+NH4+ HSO4

- NH3 SO42- NH4

+

C2H3O2-+HCl HC2H3O2+Cl- HCl C2H3O2

- Cl- HC2H3O2

HNO2+ H2O H3O++ NO2- HNO2 H2O H3O+ NO2

-

HCN+ H2O H3O++ CN- HCN H2O CN- H3O+

Conjugate Pair Solutions

pH IndicatorsIndicator Low pH color Transition pH range High pH color

Methyl Violet yellow 0.0–2.0 blue-violetLeucomalachite Green yellow 0.0–2.0 greenLeucomalachite Green green 11.6–14 colorlessThymol Blue red 1.2–2.8 yellowThymol Blue yellow 8.0–9.6 blueMethyl Yellow red 2.9–4.0 yellowBromophenol Blue yellow 3.0–4.6 purpleCongo Red blue-violet 3.0–5.0 redMethyl Orange red 3.1–4.4 orangeBromocrescol Green yellow 3.8–5.4 blue-greenMethyl Red red 4.4–6.2 yellowMethyl Red / Bromocresol green red 4.5–5.2 greenAzolitman red 4.5–8.3 blueBromocrescol Purple yellow 5.2–6.8 purpleBromothymol Blue yellow 6.0–7.6 bluePhenol Red yellow 6.8–8.4 redNeutral Red red 6.8–8.0 yellowNaphtholphthalein Colorless reddish 7.3–8.7 greenish to blueCrescol Red yellow 7.2–8.8 reddish-purplePhenolphthalein colorless 8.3–10.0 fuchsiaThymolphthalein colorless 9.3–10.5 blueAlizarine Yellow-Red yellow 10.2–12.0 redLitmus red 4.5-8.3 blue

Pre-Lab Info

• acetic (ethanoic) acid CH3COOH pKa = 4.75

• hydrochloric acid HCl pKa = -4

• sodium hydroxide NaOH pKb = 0.2

Next, web search for a tutorial on how to use a buret to perform a titration. We *may* get digital pH meters in time, but learn how to use indicator dyes as a backup plan.