1516 Lecture Notes - Lecture 8: Nitric Acid, Sodium Hydroxide, Titration

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turquoisewalrus781

9 Jun 2019

School

University of Canberra

Department

University of Canberra

Course

1516

Professor

Karen Altamore

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Document Summary

Substance that gives hydrogen ion h+ or a hydronium ion h3o+ when dissolved in water. A substance which has an acidic nature contains one or more hydrogen and an anionic group in its formula. Monoprotic : gives a single proton or hydrogen ion in aqueous solution (eg. hcl, hydrochloric acid or hno3 nitric acid) Diprotic : releases two hydrogen ions in aqueous solution (eg. h2co3, carbonic acid) Tripotic : releases three hydrogen ions in aqueous solution (eg. h3po4, phosphoric acid) Substance which gives hydroxide ion oh- when dissolved in water, it receives h+ ion s. Example : naoh, koh (common ones) > when dissolved in water they dissociate into their component ions, introducing oh- ions into the solution. Acids and bases that completely get ionised in solutions are called strong acids and strong bases. Those that are partly ionised are called weak acids and weak bases. The more stable is a reaction/compound, the stronger it will be.

Related Questions

QUESTION 1

Which of the following substances is most acidic?

		Cowâs milk - pH 6.6
		Apple juice - pH 3.0
		Tomato juice - pH 4.5
		Distilled water - pH 7.0

2 points

QUESTION 2

A buffer is a substance that converts:

Alkaline solutions to neutral solutions.

Acidic solutions to alkaline solutions.

Strong bases or acids to weak bases or acids.

Acidic solutions to neutral solutions.

QUESTION 3

How does a solution of pH 7 compare to a solution of pH 10?

		pH 7 has more OH^- ions
		pH 7 is more basic
		pH 7 has a higher pH
		pH 7 has more H⁺ ions

2 points

QUESTION 4

According to the Arrhenius Theory of acids and bases, a base is:

A substance that decrease the amount of hydroxide ions present.

A substance that increases the amount of hydroxide ions present when it is dissolved in water.

A substance that increase the amount of hydrogen ions present.

A substance that increases the amount of hydrogen ions present when it is dissolved in water.

QUESTION 5

Which of the following are true regarding acid-base titrations?

		They are used to determine the concentration of an unknown acid or base.
		The acid or the base must be a standard solution with a known concentration
		The standard solution is titrated into the chemical with the unknown concentration.
		All of the above are true regarding acid-base titrations.

2 points

QUESTION 6

Which of the following is not an example of a neutralization reaction?

HCl + NaOH NaCl +H₂O

2 NaOH + H₂CO₃ Na₂CO₃ +2 H₂O

H₂SO₄ + 2 NH₄OH (NH₄)₂SO₄ + 2 H₂O

2 AgNO₃ + Zn 2Ag +Zn(NO₃)₂

QUESTION 7

Which acid base theory defines an acid as a proton donor and a base as a proton acceptor?

		Arrhenius Theory
		Bronsted-Lowery Theory
		Conjugate Pairs Theory
		Lewis Theory

2 points

QUESTION 8

The Arrhenius Theory states that acid-base reactions create a solution composed of a water and a salt. This is because mixing an acidic and basic solution together yields:

A neutral solution

A solution with a pH at or near 7

Both A and B are correct

QUESTION 9

Which of the following correctly defines a standard solution?

		A solution which always has the same molecular geometry.
		A solution in which the concentration is precisely known.
		A solution in which the volume is precisely known.
		A solution which always has different levels of solutes and solvents.

2 points

QUESTION 10

Acids naturally present in food are generally safe to eat because they are usually:

		Concentrated
		Dilute
		Weak
		Strong

None of the above are correct

Part A A fuel cell differs from a battery because the current is being generated from a reduction-oxidation (redox) reaction in which the reactant is consumed. A classic example of a fuel cell is the phosphoric acid fuel cell (PAFC), which have been used in stationary power generators, buses, and even submarines. Fuel cells require an electrolyte (similar to batteries) to carry electrically charged species between the electrodes, and a PAFC utilizes phosphoric acid (H3PO4) as its electrolyte. Phosphoric acid has three acidic protons that can dissociate in water, as highlighted in red here: H3PO4. However, it is considered a weak acid because some of the acid will remain in molecular form when dissolved in water. Write the complete ionic equation that depicts the dissociation of the first proton for the weak acid phosphoric acid (H3PO4). Make certain you include all charges for any ions produced. Express you answer as a chemical equation including phases. Titrations as analytical neutralization reactions Neutralization reactions can occur between any combination of weak/strong acids and bases. When we want to determine the concentration of a base in solution, we can apply the concept of neutralization by reacting the base with a known amount of an acid in the presence of an indicator (a compound that changes color depending on the pH). This method of determining the concentration of a base is called acid-base titration, and it can also be used to determine the concentration of an acid by titrating it with a known amount of base. A common acid to use for titrations is potassium hydrogen phthalate (written as KHP or KHPh; do not confuse the P for phosphorus). The reason KHP is common is because it is solid at room temperature, and we can accurately mass the amount that is added to solution. As a soluble salt, KHP completely dissociates to form a potassium ion (K+) and an acidic hydrogen phthalate ion (HPâ), which is a weak acid that has only one acidic hydrogen. This ionization is depicted below. KHP(s) â K+(aq)+HPâ(aq) Although ionization (the formation of ions) occurs as a result of acid dissociation for most weak acids, KHP ionizes before acid dissociation occurs. In other words, HPâ is a weak acid ion. Part C If you wanted to determine how much KOH (potassium hydroxide; a strong base) was dissolved in water, you could titrate it with a known amount of KHP (potassium hydrogen phthalate; a weak acid) until a color change indicates that the base is completely neutralized. The molecular equation below depicts this neutralization reaction. KHP(aq)+KOH(aq)âK2P(aq)+H2O(l) Write the net ionic equation that depicts the neutralization of the base by potassium hydrogen phthalate. Instead of using the entire chemical formula of phthalate, use HPâ to represent the acidic hydrogen phthalate ion and P2â to represent the phthalate ion. Express your answer as a net ionic equation including phases.

x.Hm1. Which chemical equation shows the dissociation of 2 protonsfrom trihydrogen phosphate (phosphoric acid)? (Points: 1)
H₃PO₄Â®H₂⁺ + HPO₄Â¯
H₃PO₄Â®H₂²⁺ + PO₄²Â¯
H₃PO₄Â®2H⁺ + HPO₄²Â¯
H₃PO₄Â®H₃³⁺ + PO₄³Â¯

2. When dissolved in water, hydrogen bromide(HBr)forms hydrobromic acid. Determine the hydroxide ion concentrationina 4,500 mL solution containing 3.78 g hydrogen bromide;K_w = 1.00 Â´ 10Â¯¹⁴. (Points: 1)
[OHÂ¯] = 9.63 Â´ 10Â¯¹³M
[OHÂ¯] = 2.14 Â´ 10Â¯¹³M
[OHÂ¯] = 4.67 Â´ 10Â¯²M
[OHÂ¯] = 0.0104 M

3. The hydronium ion concentration in asolutionwith pH 10 is __________ than the hydronium ion concentrationin asolution with pH 13. (Points: 1)
1,000 times less
3 times greater
1,000 times greater
100 times less

4. Which reaction most accurately represents thedissociation of nitrous acid (HNO₂) in water? (Points:1)
HNO₂ +H₂O Â® H₃O⁺ + NO₂Â¯
HNO₂ +H₂O Â® H₃O₂⁺ + NOÂ¯
HNO₂ +H₂O Â® HN + HO⁺ + HO₂Â¯
HNO₂ +H₂O Â® H₃O⁺ + N +O₂Â¯

5. The acid neutralizing capacity of a lakeorstream most often derives from the presence of _______ inthesurrounding soil or rock. (Points: 1)
CaCO₃
HNO₃
NaCl
Sr(OH)₂

6. Bases produce which ions in aqueous solution?(Points: 1)
OHÂ¯
NO₂Â¯
ClÂ¯
SO₃Â¯

7. The primary product of the combustion of sulfuris: (Points: 1)
H₂S
H₂SO₄
H₂SO₃
SO₂

8. Which solution is acidic? (Points: 1)
M_OHÂ¯ = 0.0065M
M_H+ = 1.27 Â´10Â¯⁹ M
M_H+ = 5.79 Â´10Â¯¹⁰ M
M_OHÂ¯ = 1.77 Â´10Â¯¹⁰ M

9. An acidic fog in Pasadena was found to have apH of 2.50. Which expression represents this pH measurement?(Points: 1)
M_OHÂ¯ = 3.2 Â´10Â¯¹² M
M_OHÂ¯ = 3.2 Â´10Â¯⁹ M
M_H+ = 9.7 Â´10Â¯³ M

1516 Lecture Notes - Lecture 8: Nitric Acid, Sodium Hydroxide, Titration

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