Cuestionario: Inorganic Ion Fundamentals — 10 preguntas

1. Which ion is commonly used as a biological buffer in blood?

A. Bicarbonate (HCO₃⁻)

B. Sulfate (SO₄²⁻)

C. Permanganate (MnO₄⁻)

D. Nitrate (NO₃⁻)

Answer: (A)

Explicación

Bicarbonate (HCO₃⁻) acts as a crucial buffer in blood, helping to maintain pH stability by neutralizing excess acids or bases. It plays a vital role in the carbon dioxide transport and pH regulation in biological systems.

2. Which inorganic ion is commonly involved in the nitrogen cycle as both nitrite and nitrate?

A. Nitrate (NO₃⁻)

B. Ammonium (NH₄⁺)

C. Nitrite (NO₂⁻)

D. Sulfate (SO₄²⁻)

Answer: (A)

Explicación

Nitrate (NO₃⁻) and nitrite (NO₂⁻) are key nitrogen ions in the nitrogen cycle, involved in processes like nitrification and denitrification, with nitrate being more oxidized.

3. What is the oxidation state of chromium in dichromate (Cr₂O₇²⁻)?

A. +3

B. +6

C. +4

D. +2

Answer: (B)

Explicación

In dichromate (Cr₂O₇²⁻), each chromium atom has an oxidation state of +6. This is because the overall charge of the ion is -2, and with seven oxygens each at -2, the total negative charge is -14. To balance, each chromium must be +6, since 2×(+6) + 7×(-2) = -2.

4. Which sulfur ion has the highest oxidation state, making it the most oxidized form?

A. Sulfite (SO₃²⁻)

B. Sulfate (SO₄²⁻)

C. Thiosulfate (S₂O₃²⁻)

D. Hydrogen sulfide (H₂S)

Answer: (B)

Explicación

Sulfate (SO₄²⁻) has sulfur in the +6 oxidation state, making it the most oxidized sulfur ion among those listed, whereas sulfite has sulfur in +4 oxidation state.

5. Which of the following ions is a strong oxidizing agent commonly used in chemistry?

A. Sulfite (SO₃²⁻)

B. Permanganate (MnO₄⁻)

C. Chloride (Cl⁻)

D. Hydroxide (OH⁻)

Answer: (B)

Explicación

Permanganate (MnO₄⁻) is a powerful oxidizing agent widely used in chemical reactions, analytical chemistry, and disinfection. It readily accepts electrons, reducing from Mn in +7 oxidation state to lower states.

6. What is the primary biological significance of phosphate ions (PO₄³⁻)?

A. They serve as buffers in blood.

B. They are components of ATP, DNA, bones, and teeth.

C. They act as strong oxidizing agents.

D. They are used in industrial disinfectants.

Answer: (B)

Explicación

Phosphate ions are vital in biological systems as part of ATP, DNA, and structural components like bones and teeth, reflecting their importance in energy transfer and genetic material.

7. Which halogen oxyanion has the highest oxidation state of chlorine?

A. Hypochlorite (ClO⁻)

B. Chlorite (ClO₂⁻)

C. Chlorate (ClO₃⁻)

D. Perchlorate (ClO₄⁻)

Answer: (D)

Explicación

Perchlorate (ClO₄⁻) contains chlorine in the +7 oxidation state, which is the highest among the oxyanions listed, indicating its strong oxidizing ability.

8. Chromate and dichromate ions are known for what characteristic in redox reactions?

A. They act as reducing agents.

B. They are weak oxidizers.

C. They are potent oxidizers and are carcinogenic.

D. They are biologically inert.

Answer: (C)

Explicación

Chromate (CrO₄²⁻) and dichromate (Cr₂O₇²⁻) ions are strong oxidizers used in various industrial processes, but they are also known to be carcinogenic.

9. Which ion is a common strong oxidant used in redox reactions and is known for its vivid purple color?

A. Permanganate (MnO₄⁻)

B. Cyanide (CN⁻)

C. Ammonium (NH₄⁺)

D. Chlorite (ClO₂⁻)

Answer: (A)

Explicación

Permanganate (MnO₄⁻) is a well-known strong oxidant used in analytical chemistry and displays a distinctive violet color, making it easily identifiable.

10. Which of the following acids is NOT typically considered an inorganic acid?

A. Sulfuric acid (H₂SO₄)

B. Nitric acid (HNO₃)

C. Phosphoric acid (H₃PO₄)

D. Acetic acid (CH₃COOH)

Answer: (D)

Explicación

Acetic acid is an organic acid, derived from acetic acid bacteria, whereas sulfuric, nitric, and phosphoric acids are inorganic acids commonly encountered in inorganic chemistry.