Metals, Minerals, Ores Properties, Uses MCQs with Explanations
Metals, Minerals, Ores Properties, Uses covers the occurrence of metals in nature, metallurgical extraction processes, physical properties, and industrial applications.
Correct Answer:
(D)
Potassium
Among the given options, Potassium is the most reactive metal. The given metals in order of reactivity are- Potassium (K) > Sodium (Na) > Calcium (Ca) > Iron (Fe).
Ques: 2
Which one of the following is the hardest metal?
Correct Answer:
(D)
Tungsten
Among all natural materials, diamond is the hardest (which is non-metal) whereas, among the metals, Tungsten is the hardest.
Ques: 3
Which one of the following materials is very hard and very ductile ?
Correct Answer:
(D)
Nichrome
Nichrome (NiCr, nickel-chrome, chrome-nickel, etc.) generally refers to any alloy of Nickel, Chromium and often Iron and/or other elements or substances. Nichrome is very hard and very ductile material. It has high specific resistively and minimum temperature coefficient. It also has the ability to operate at high temperature. Nichrome alloys are typically restorations (fillings) and in other applications.
Ques: 4
The heaviest natural element is ?
Correct Answer:
(A) Uranium
Uranium is the heaviest naturally occurring element with an atomic no. of 92. It is a pure form of silver-coloured heavy metal. Its most common isotope Uranium-238 has a nucleus containing 92 protons and 146 neutrons. It has a density of 19.05 g/cm3.
Ques: 5
The chemical structure of the pearl is –
Correct Answer:
(A) Calcium Carbonate
The chemical composition of pearl is 85% Calcium Carbonate (Aragonite), 10-14% Conchiolin and 2-4% of water (CaCO3 and H2O). Conchiolin is a protein.
Ques: 6
What are Rubies and Sapphires chemically known as?
Correct Answer:
(B) Aluminium Oxide
Aluminium Oxide is a chemical compound of Aluminium and Oxygen with the chemical formula Al2O3. Corundum is the most common naturally occurring crystalline form of Aluminium Oxide. Rubies and Sapphires are gem-quality in forms of Corundum which owe their characteristic colours to trace impurities.
Ques: 7
Consider the following statements:
Assertion (A) : Sodium metal is stored under kerosene.
Reason (R) : Metallic sodium melts when exposed to air.
(a) Both
(A) and (R) are true, and (R) is the correct explanation of
(A).
(b) Both
(A) and (R) are true, but (R) is not a correct explanation of
(A).
Correct Answer:
(C)
Sodium is kept in kerosene to prevent it from coming in contact with oxygen present in the air. If this happens, it will react with the oxygen and form sodium oxide. This is a strongly exothermic reaction and a lot of heat is generated. Thus, Sodium is kept under kerosene.
Ques: 8
These days yellow lamps are frequently used as street light. Which one of the following is used in these lamps :
Correct Answer:
(A) Sodium
There are 2 types of street light lamps which are used by municipalities. They are sodium vapor and mercury vapor lamps. The mercury vapor lamps have usually a white ambient light and sodium vapor lamps have orange/yellow light. Compared to LPS (Low-pressure sodium) lamps, high- pressure sodium lamps tend to have a longer life, less lumen per watt efficiency and most importantly a higher colour rendering index.
Ques: 9
Sodium Vapor Lamp is usually used as street light, because –
Correct Answer:
(B) Light from this is monochromatic and will not split through water droplets.
A sodium-vapor lamp is a gas-discharge lamp that uses sodium in an excited state to produce light. Low-pressure sodium lamps only give monochromatic yellow light and so inhibit colour vision at night and will not split through water droplets. Sodium-vapor lamps cause less light pollution than mercury-vapor lamps.
Ques: 10
Which one of the following metals is accessed in the native state ?
Correct Answer:
(B) Gold
Among the given metals, gold is the least reactive, so this was accessed in the native (free) state. Only gold, silver, copper and platinum metals occur in native state in nature in large amounts.
Ques: 11
Of how many carats is the pure gold?
Correct Answer:
(B) 24
It is an extension of the older carat (Karat in American spelling) system of denoting the purity of gold by fractions of 24, such as '18 carat' for an alloy with 75% (18 parts per 24) pure gold by mass. Because of the softness of pure (24 carat) gold, it is usually alloyed with base metals for use in jewellery, altering its hardness and ductility, melting point, colour and other properties. Alloys with lower carat rating typically 22k, 18k, 14k or 10k contain higher percentages of copper or other base metals or silver or palladium in the alloy.
Ques: 12
Minerals are-
Correct Answer:
(B) Inorganic solids
According to Geologists, minerals are naturally occurring inorganic substances with a definite and predictable chemical composition and physical properties.
Ques: 13
The softest mineral, Talc (Soapstone) is mainly :
Correct Answer:
(D)
Magnesium Silicate
Talc is a mineral which is composed of hydrated Magnesium silicate with formula Mg3 Si4O10(OH)2. On the Mohs hardness scale, the softest mineral talc is rated 1 and the hardest mineral, the diamond is rated 10. In loose form, talc is the widely used substance known as a baby powder (aka talcum). It occurs as foliated to fibrous masses and in an exceptionally rare crystal form.
Ques: 14
The chemical name of limestone is?
Correct Answer:
(A) Calcium Carbonate
Limestone is a sedimentary rock composed largely of the minerals Calcite and Aragonite which are different crystal forms of Calcium Carbonate (CaCO3). Limestone binds with silica and other impurities to remove them from the iron.
Ques: 15
'Plaster of Paris' is made up of
Correct Answer:
(C) Gypsum
Plaster of Paris is a white powdery slightly hydrated calcium sulfate (CaSO4.1/2 H2O) made by calcining gypsum and used mainly for casts and molds in the form of a quick-setting paste with water.
Ques: 16
Which one of the following materials contains calcium?
Correct Answer:
(C) Gypsum
Gypsum is a soft sulfate mineral which contains calcium. It is composed of calcium sulphate dihydrate, with the chemical formula CaSO4.2H2O. It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard/sidewalk chalk, and drywall.
Ques: 17
Monazite is an ore of –
Correct Answer:
(B) Thorium
Monazite is an important ore for Thorium, Lanthanum and Cerium. India, Madagascar and South Africa have large deposits of monazite sands. The deposits in India are particularly rich in Monazite. Its extensive deposits are found in Southern India.
Ques: 18
Mica is a :
Correct Answer:
(A) Good conductor of heat and bad conductor of electricity
(1) Good conductors of electricity are : Aluminum, Brass, Copper, Iron, Steel
(2) Bad conductors of electricity are : Acrylic, China clay, Glass, Mica, Paper, Plastic & Wood. Mica is a bad conductor of electricity but a good conductor of heat. It is used as a raw material in electrical industry.
Ques: 19
Which among the following liquids is the best conductor of heat?
Correct Answer:
(A) Mercury
Mercury is a chemical element with the symbol (Hg). Mercury is used in thermometers due to its special properties. It can measure a wide range of temperatures from -40 to 356oC and up to 570oC under pressure in a liquid state. It expands regularly in proportional to the absolute temperature changes. A heavy, silvery d-block element, mercury is the only common metal element which is found in liquid state at standard conditions for temperature and pressure. It is a metal, so it is a conductor of heat. Mercury is the poorest conductor of heat among all metals, but among the given options it is the best conductor of heat.
Ques: 20
The poorest conductor of heat among the following is :
Correct Answer:
(C) Mercury
All metals are conductors of heat but lead and mercury are poor conductors of heat compared to other metals. Thermal conductivity of lead is about 34.7 w/mK while thermal conductivity of mercury is only about 8.31 w/mK. Hence, mercury is the poorest conductor of heat among all metals.
Ques: 21
Which one of the following metals is liquid at ordinary temperature?
Correct Answer:
(C) Mercury
Mercury is the only common metal which is liquid at ordinary (room) temperature. Mercury is sometimes called quicksilver.
Ques: 22
Which of the following is in liquid form at room temperature?
Correct Answer:
(C) Francium
There are two elements Bromine and Mercury that are liquid at the room temperature (298 K or 25oC). There are four more elements which melt just a few degree above room temperature. These are Francium, Caesium, Gallium and Rubidium.