Metallurgy, Metals, Non-Metals & Alloy RRB PYQ

Aluminum is the most abundant metal in Earth's crust. It is highly reactive and doesn't occur in its pure form naturally. Ranking third after oxygen and silicon, it is primarily extracted from bauxite ore (Al2O3.nH2O). This ore contains 30% to 70% aluminum oxide.

Carbon is a non-metal with an atomic number of 6 and atomic mass of 12. It forms covalent bonds by sharing four electrons and exists in various allotropes like diamond and graphite, each with distinct properties. Carbon is generally inert under normal conditions, and it is symbolized as C in the periodic table.

According to the reactivity series, iron is more reactive than copper. Iron is less reactive than potassium, sodium, and calcium. Potassium, sodium, and calcium are highly reactive metals. Copper, a less reactive metal, is placed below iron in the reactivity series.

One carbon atom is covalently doubly linked to two oxygen atoms in each of the molecules that make up carbon dioxide. At room temperature, it exists as a gas. In the atmosphere, carbon dioxide serves as a greenhouse gas because it absorbs infrared radiation despite being transparent to visible light.

Mercury, a highly toxic element, was traditionally used in thermometers due to its unique properties, including expansion and contraction with temperature changes. The use of mercury in thermometers has declined globally due to environmental and health concerns associated with its toxicity.

Let the total quantity of the alloy be x grams. Since 42% of this alloy is silver: x x 42/100 = 147, so x = 147 x 100/42 = 350 g. The quantity of the other elements in the alloy is: 350 - 147 = 203 g.

Graphite, an allotrope of carbon, is used as a dry lubricant due to its slippery nature and ability to provide lubrication at high temperatures. It is often preferred over liquid and oil lubricants. Graphite's applications include the food industry, air compressors, machine shops, locks, piano actions, ball bearings, open gears, and brass instrument valves.

Sodium is highly reactive with air and water, so it is stored under kerosene oil to prevent it from reacting with atmospheric moisture and oxygen.

Mercury is a liquid at room temperature. Sodium is a soft, solid metal at room temperature that reacts readily with water and oxygen in the air. Calcium is also a solid metal at room temperature with a silvery-white appearance and is relatively reactive. Lithium is a soft, light metal that is solid at room temperature and is the lightest of all alkali metals.

Nichrome is primarily composed of nickel (Ni), chromium (Cr), manganese (Mn), and iron (Fe). This alloy is known for its high resistance to oxidation and corrosion, making it ideal for use in heating elements. Nichrome's high melting point and electrical resistivity also make it suitable for applications requiring stable performance at high temperatures.