1: What is the atomic number of Manganese on the periodic table?
A: 24
B: 25
C: 26
D: 27
Correct Answer: B
Explanation: Manganese is represented by the atomic number 25 on the periodic table.
2: Who isolated manganese metal for the first time?
A: Carl Wilhelm Scheele
B: Johann Gottlieb Gahn
C: Ignatius Gottfried Kaim
D: Johan Glauber
Correct Answer: B
Explanation: Johann Gottlieb Gahn isolated manganese metal in 1774 by reducing manganese dioxide with carbon.
3: What is the primary use of manganese in industry?
A: Aluminum production
B: Glass making
C: Battery manufacturing
D: Steel production
Correct Answer: D
Explanation: Manganese is essential in steel production due to its sulfur-fixing, deoxidizing, and alloying properties.
4: What important enzyme found in plants involves a Mn-O cluster?
A: Amylase
B: Hemoglobin
C: Oxygen-evolving complex
D: DNA polymerase
Correct Answer: C
Explanation: The oxygen-evolving complex in plants uses a Mn-O cluster during photosynthesis to produce oxygen.
5: How is manganese primarily found in nature?
A: As a pure metal
B: In combination with iron
C: As a gas
D: Dissolved in water
Correct Answer: B
Explanation: Manganese is often found in minerals in combination with iron.
6: What is the common oxidation state of manganese in potassium permanganate?
A: +2
B: +4
C: +6
D: +7
Correct Answer: D
Explanation: In potassium permanganate (KMnO4), manganese has an oxidation state of +7.
7: What is the melting point of manganese?
A: 1246°C
B: 1519°C
C: 2061°C
D: 2334°C
Correct Answer: A
Explanation: The melting point of manganese is 1519 K (1246°C).
8: What type of crystal structure does alpha-manganese (α-Mn) have?
A: Face-centered cubic
B: Body-centered cubic
C: Hexagonal close-packed
D: Simple cubic
Correct Answer: B
Explanation: Alpha-manganese (α-Mn) has a body-centered cubic (bcc) crystal structure.
9: What role does manganese play in the human body?
A: Bone formation and macronutrient metabolism
B: Muscle contraction
C: Blood pressure regulation
D: Vision
Correct Answer: A
Explanation: Manganese is an essential human dietary element important for bone formation and macronutrient metabolism.
10: Which scientist is credited with using manganese dioxide to produce chlorine?
A: Carl Wilhelm Scheele
B: James Couper
C: Robert Forester Mushet
D: Mas Subramanian
Correct Answer: A
Explanation: Carl Wilhelm Scheele used manganese dioxide in the production of chlorine.
11: From which mineral is manganese dioxide typically extracted?
A: Pyrolusite
B: Rhodochrosite
C: Hematite
D: Sphalerite
Correct Answer: A
Explanation: Pyrolusite is the most common mineral from which manganese dioxide is extracted.
12: Manganese improves which property of stainless steels?
A: Color
B: Weight
C: Strength and resistance to wear
D: Melting point
Correct Answer: C
Explanation: Manganese improves the strength and resistance to wear of stainless steels.
13: What is the density of manganese at 20°C?
A: 5.95 g/cm3
B: 7.476 g/cm3
C: 9.04 g/cm3
D: 10.5 g/cm3
Correct Answer: B
Explanation: The density of manganese at 20°C is 7.476 g/cm3.
14: What is the chemical symbol for manganese?
A: Ma
B: Mg
C: Mn
D: Mo
Correct Answer: C
Explanation: The chemical symbol for manganese is Mn.
15: What is manganese’s phase at standard temperature and pressure (STP)?
A: Gas
B: Liquid
C: Solid
D: Plasma
Correct Answer: C
Explanation: At STP, manganese is a solid metal.
16: In what form is manganese familiar in laboratory settings?
A: Elemental gas
B: Potassium permanganate (deep violet salt)
C: Manganese carbonate (rhodochrosite)
D: Pure manganese cubes
Correct Answer: B
Explanation: Manganese is familiar in laboratories as the deep violet salt potassium permanganate.
17: Which isotope of manganese is stable?
A: 53Mn
B: 54Mn
C: 55Mn
D: 56Mn
Correct Answer: C
Explanation: 55Mn is the only stable isotope of manganese.
18: How does manganese typically react in oxidized water?
A: It remains inert
B: It dissolves
C: It rusts like iron
D: It forms a gas
Correct Answer: C
Explanation: Manganese oxidizes or “rusts” in water containing dissolved oxygen, similar to iron.
19: What color is associated with manganese(II) chloride crystals?
A: Deep purple
B: Pale pink
C: Green
D: Dark brown
Correct Answer: B
Explanation: Manganese(II) chloride crystals typically exhibit a pale pink color due to a spin-forbidden 3d transition.
20: What is an example of a manganese compound with oxidation state +7?
A: Manganese dioxide
B: Potassium permanganate
C: Manganese sulfate
D: Manganese carbonate
Correct Answer: B
Explanation: Potassium permanganate contains manganese in the +7 oxidation state.
21: Which substance is produced using manganese dioxide by alchemists?
A: Iron
B: Lead
C: Chlorine
D: Silver
Correct Answer: C
Explanation: Alchemists used manganese dioxide to produce chlorine, especially Carl Wilhelm Scheele.
22: What year is attributed to the isolation of manganese metal by Johan Gottlieb Gahn?
A: 1750
B: 1774
C: 1800
D: 1850
Correct Answer: B
Explanation: Johan Gottlieb Gahn first isolated manganese metal in 1774.
23: Which country contributes 80% of the world’s manganese resources?
A: Australia
B: China
C: South Africa
D: Brazil
Correct Answer: C
Explanation: South Africa holds about 80% of the world’s known manganese resources.
24: What is the primary decay mode for manganese isotopes lighter than 55Mn?
A: Alpha decay
B: Electron capture
C: Gamma decay
D: Neutron emission
Correct Answer: B
Explanation: The primary decay mode for isotopes lighter than 55Mn is electron capture.
25: What is an allotrope of manganese that forms when heated above 1,370 K?
A: Alpha manganese
B: Beta manganese
C: Gamma manganese
D: Delta manganese
Correct Answer: C
Explanation: Gamma manganese forms when manganese is heated above 1,370 K.
26: What is the primary geographic feature associated with South African manganese deposits?
A: Magaliesberg Range
B: Drakensberg Mountains
C: Kalahari manganese fields
D: Table Mountain
Correct Answer: C
Explanation: Most identified South African manganese deposits are located in the Kalahari manganese fields.
27: Which country’s project was Hughes Glomar Explorer linked to regarding manganese nodules?
A: United States
B: Soviet Union
C: United Kingdom
D: France
Correct Answer: A
Explanation: The Hughes Glomar Explorer was an American project, secretly intended to raise a Soviet submarine.
28: Manganese IV oxide is commonly used in which type of battery?
A: Lead-acid
B: Alkaline
C: Lithium-ion
D: Nickel-cadmium
Correct Answer: B
Explanation: Manganese(IV) oxide is used in alkaline batteries as a cathodic depolarizer.
29: Which metal does manganese addition to aluminum help resist?
A: Magnesium
B: Copper
C: Iron
D: Nickel
Correct Answer: C
Explanation: Manganese in aluminum alloys helps resist galvanic corrosion, often involving iron impurities.
30: How does manganese toxicity usually affect workers?
A: Respiratory failure
B: Gastrointestinal issues
C: Neurological disorders
D: Skin irritation
Correct Answer: C
Explanation: Manganese overexposure in workers often leads to neurological disorders.
31: What are minerals like psilomelane and braunite primarily composed of?
A: Silicate
B: Carbonate
C: Sulfate
D: Oxide
Correct Answer: D
Explanation: Minerals like psilomelane and braunite are primarily composed of manganese oxides.
32: Manganese is essential for which critical body function?
A: Blood sugar regulation
B: Muscle contraction
C: Bone formation
D: Nerve transmission
Correct Answer: C
Explanation: Manganese is essential for bone formation and other biological processes.
33: Which metal does manganese often substitute in steel to avoid forming iron sulfide?
A: Sulfur
B: Phosphorus
C: Carbon
D: Nickel
Correct Answer: A
Explanation: Manganese in steel substitutes for sulfur to prevent forming iron sulfide at grain boundaries.
34: How many oxidation states does manganese exhibit?
A: 2
B: 4
C: 6
D: 8
Correct Answer: D
Explanation: Manganese exhibits oxidation states from -3 to +7, showing its versatile chemistry.
35: What are the manganese containing gases called that are added to some gasolines?
A: Methylcyclopentadienyl manganese tricarbonyl (MMT)
B: Potassium permanganate
C: Ferrate
D: Magnesium sulfide
Correct Answer: A
Explanation: Methylcyclopentadienyl manganese tricarbonyl (MMT) is added to gasolines to improve octane rating.
36: What metal is combined with manganese to create Hadfield steel?
A: Nickel
B: Chromium
C: Iron
D: Copper
Correct Answer: C
Explanation: Hadfield steel is created by combining high amounts of manganese with iron.
37: What pigment was discovered combining manganese with yttrium and indium?
A: Prussian blue
B: Cobalt blue
C: Egyptian blue
D: YInMn blue
Correct Answer: D
Explanation: YInMn blue pigment combines manganese with yttrium and indium, discovered at Oregon State University.
38: What is the common effect of manganese deficiency in humans?
A: Vision problems
B: Liver malfunction
C: Skeletal deformation
D: Heart diseases
Correct Answer: C
Explanation: Manganese deficiency can lead to skeletal deformation due to inhibited collagen production in wound healing.
39: Which form does manganese take when found in marine environments?
A: Dissolved manganese (dMn)
B: MnO2 mineral deposits
C: Metallic nodules
D: Manganese sulfate
Correct Answer: A
Explanation: Manganese in marine environments is often found as dissolved manganese (dMn), especially around hydrothermal vents.
40: What is the half-life of the manganese isotope 53Mn?
A: 3.7 million years
B: 312.2 days
C: 5.591 days
D: Less than 3 hours
Correct Answer: A
Explanation: The half-life of the manganese isotope 53Mn is 3.7 million years.
41: What are the oxidation states of manganese oxide most commonly found in dry cell batteries?
A: +2 and +3
B: +4 and +6
C: +4 and +2
D: +6 and +7
Correct Answer: C
Explanation: In dry cell batteries, manganese oxide is commonly found in the +4 (MnO2) and +2 (Mn(OH)2) oxidation states.
42: Which manganese compound is used as a fungicide in agriculture?
A: Manganese sulfate
B: Manganese dioxide
C: Manganese(III) acetate
D: Potassium permanganate
Correct Answer: A
Explanation: Manganese sulfate is used as a fungicide in agriculture.
43: What is the lattice constant of α-Mn at 20°C?
A: 891.16 pm
B: 1015.25 pm
C: 785.50 pm
D: 925.35 pm
Correct Answer: A
Explanation: The lattice constant of α-Mn at 20°C is 891.16 pm.
44: Which manganese alloy is used in combat helmets?
A: Ferritic steel
B: Hadfield steel
C: Inconel alloy
D: Kovar
Correct Answer: B
Explanation: Hadfield steel, containing high levels of manganese, was used in combat helmets, such as the U.S. M1917.
45: What is a notable property of manganese(II) ions in terms of color?
A: Bright yellow
B: Pale pink
C: Deep green
D: Colorless
Correct Answer: B
Explanation: Manganese(II) ions typically exhibit a pale pink color in solution.
46: In the context of fuel additives, what is the primary use of methylcyclopentadienyl manganese tricarbonyl (MMT)?
A: To provide fuel luminescence
B: As a corrosion inhibitor
C: As an anti-knock agent
D: To clean fuel injectors
Correct Answer: C
Explanation: Methylcyclopentadienyl manganese tricarbonyl (MMT) is used as an anti-knock agent in gasoline.
47: What mineral is the main source of manganese used in industrial applications?
A: Hematite
B: Pyrolusite
C: Magnetite
D: Quartz
Correct Answer: B
Explanation: Pyrolusite (MnO2) is the main source of manganese for industrial applications.
48: Where in the body is manganese mostly stored?
A: In the brain
B: In the bones
C: In the liver
D: In the muscles
Correct Answer: B
Explanation: Manganese is mostly stored in the bones of the human body.
49: What type of industrial process was innovated due to manganese’s role in electrochemical coatings?
A: Galvanization
B: Electroplating
C: Manganese phosphate coatings
D: Anodizing
Correct Answer: C
Explanation: Manganese phosphate coatings are used to protect firearms and other materials against rust and corrosion.
50: Which major steel property is improved by adding small amounts of manganese?
A: Electrical conductivity
B: Thermal resistance
C: High-temperature workability
D: Reflectivity
Correct Answer: C
Explanation: Small amounts of manganese improve the high-temperature workability of steel.
51: What is the primary biological role of manganese in humans related to enzyme function?
A: DNA synthesis
B: Oxygen transport
C: Act as a coenzyme for metabolic processes
D: Cell signaling
Correct Answer: C
Explanation: Manganese acts as a coenzyme in several biological processes, including macronutrient metabolism.
52: What effect does manganese have on glass?
A: Darkens it
B: Increases its density
C: Neutralizes greenish tinge from iron
D: Makes it more brittle
Correct Answer: C
Explanation: Manganese neutralizes the greenish tinge in glass caused by trace amounts of iron contamination.
53: What is a noticeable symptom of excessive manganese exposure?
A: Skin rash
B: Breathing difficulties
C: Nerve damage similar to Parkinson’s disease
D: Hearing loss
Correct Answer: C
Explanation: Excessive manganese exposure can cause manganism, characterized by symptoms similar to Parkinson’s disease.
54: In what year did Carl Wilhelm Scheele use manganese dioxide to produce chlorine?
A: 1756
B: 1764
C: 1774
D: 1786
Correct Answer: C
Explanation: Carl Wilhelm Scheele used manganese dioxide to produce chlorine in 1774.
55: Manganese can be mined from which marine resource?
A: Coral reefs
B: Plankton deposits
C: Seafloor manganese nodules
D: Submarine hydrothermal vents
Correct Answer: C
Explanation: Manganese can be extracted from seafloor manganese nodules, though practical harvesting remains a challenge.
56: Why is manganese used in fertilizers?
A: To increase soil pH
B: It’s a nutrient required for plant growth
C: As a pesticide
D: To improve soil drainage
Correct Answer: B
Explanation: Manganese is an important nutrient for plant growth and is thus used in fertilizers.
57: Which industry primarily consumes manganese due to its deoxidizing properties?
A: Textile
B: Agriculture
C: Construction
D: Metallurgy
Correct Answer: D
Explanation: Manganese is primarily consumed by the metallurgy industry for its deoxidizing properties, especially in steel production.
58: What is the phase transition temperature for beta-manganese (β-Mn)?
A: 700°C
B: 1100°C
C: 1300°C
D: 1400°C
Correct Answer: A
Explanation: Beta-manganese (β-Mn) forms when heated above 700°C.
59: What physiological structure in plants involves a cluster of manganese atoms?
A: Stomata
B: Oxygen-evolving complex in chloroplasts
C: Root rhizomes
D: Plant cell walls
Correct Answer: B
Explanation: The oxygen-evolving complex in chloroplasts involves a cluster of manganese atoms, crucial for photosynthesis.
60: What type of bonding is most significant in the organometallic chemistry of manganese?
A: Ionic bonding
B: Covalent bonding
C: Metallic bonding
D: Hydrogen bonding
Correct Answer: B
Explanation: Covalent bonding is significant in the organometallic chemistry of manganese, especially in compounds with Mn-C bonds.