Metals, Minerals, Ores: Properties, Uses

Which one of the following statements about alkaline earth metals is NOT true ?

[amp_mcq option1=”Strontium salts burn with a red flame” option2=”Barium metal is used in medicine to examine the alimentary canal of a patient by X-ray” option3=”Green plants need magnesium in order to make the chlorophyll that trap the energy from sunlight in photosynthesis” option4=”Red colour of gemstone Ruby is due to the element beryllium present in it” correct=”option2″]

The statement “Barium metal is used in medicine to examine the alimentary canal of a patient by X-ray” is NOT true.

For X-ray examination of the alimentary canal (Barium meal), a suspension of Barium *sulfate* (BaSO4) is used as a contrast medium. Barium sulfate is very insoluble and thus passes through the digestive system safely. Barium *metal* is highly reactive and toxic, and would react with water or acids in the body, making it unsuitable and dangerous for internal consumption or medical use in this manner.

A) Strontium salts (e.g., SrCl2) do burn with a red flame, used in fireworks. C) Magnesium is a crucial component of chlorophyll, essential for photosynthesis in green plants. D) The red colour of ruby is due to the presence of chromium ions (Cr3+) substituted into the aluminum oxide (Al2O3) lattice; beryllium is a component of other gemstones like emerald (which is beryl, a beryllium aluminum silicate, colored by chromium or vanadium). Statements A, C, and D are all factual statements (or factually correct denials, in the case of D’s claim about beryllium). Statement B is factually incorrect regarding the *form* of Barium used in medicine.

Magnesium is used in

[amp_mcq option1=”fireworks to make a bright white light” option2=”gemstones in jewellery” option3=”examination of alimentary canal of the patient” option4=”purification of water” correct=”option1″]

Magnesium is used in fireworks to make a bright white light.

Magnesium metal burns rapidly in air with a brilliant white flame, producing magnesium oxide (MgO). This property makes it useful in fireworks, flares, and incendiary devices to create intense light.

B) Gemstones in jewellery are typically minerals like corundum (ruby, sapphire), diamond, beryl, etc., which do not primarily contain magnesium as a main component providing aesthetic value in this context. C) Examination of the alimentary canal often uses Barium sulfate (BaSO4) as a contrast medium in X-rays, not magnesium. D) While magnesium compounds can be involved in water treatment (e.g., precipitating impurities), magnesium metal itself is not typically used directly for purification of water.

Aluminium, Iron, Copper and Zinc are extracted from

[amp_mcq option1=”Bauxite, Magnetite, Malachite and Calamine respectively” option2=”Magnetite, Bauxite, Malachite and Calamine respectively” option3=”Calamine, Malachite, Magnetite and Bauxite respectively” option4=”Malachite, Magnetite, Bauxite and Calamine respectively” correct=”option1″]

The correct option is A.

Aluminium is primarily extracted from Bauxite ore (hydrated aluminium oxide, Al₂O₃·nH₂O). Iron is commonly extracted from Magnetite (Fe₃O₄) or Hematite (Fe₂O₃). Copper is extracted from various ores, including Malachite (copper carbonate hydroxide, Cu₂(CO₃)(OH)₂) and Chalcopyrite (CuFeS₂). Zinc is extracted from ores like Calamine (Zinc Carbonate, ZnCO₃) or Sphalerite (Zinc Sulphide, ZnS). Option A correctly matches each metal with one of its principal ores in the specified order: Aluminium (Bauxite), Iron (Magnetite), Copper (Malachite), and Zinc (Calamine).

Other important ores for Iron include Hematite, Limonite, and Siderite. Besides Malachite, Cuprite and Azurite are also important copper ores. Sphalerite is another major zinc ore. The extraction processes for these metals involve various stages like mining, concentration, roasting, smelting, and refining.

Which one of the following gemstones contains beryllium metal?

[amp_mcq option1=”Topaz” option2=”Emerald” option3=”Ruby” option4=”Blue sapphire” correct=”option2″]

The correct answer is B) Emerald.

Emerald is a variety of the mineral beryl, with the chemical formula Be₃Al₂(SiO₃)₆. The chemical composition clearly shows the presence of Beryllium (Be) metal. The green color of emerald comes from trace amounts of chromium or vanadium within the crystal lattice.

Let’s look at the composition of the other gemstones:
– Topaz: Aluminium and fluorine silicate (Al₂SiO₄(F,OH)₂). Contains Aluminium, Silicon, Oxygen, Fluorine, Hydrogen.
– Ruby and Blue Sapphire: Both are varieties of the mineral corundum, which is aluminium oxide (Al₂O₃). Ruby is colored by chromium, and sapphire by iron and titanium.
Thus, out of the given options, only Emerald contains beryllium.