Metallurgy, Metals, Non-Metals & Alloy RRB PYQ

Statement-I: Graphite is a good conductor of electricity due to the presence of free electrons in its structure. This makes it incorrect. Statement-II: In graphite, each carbon atom is bonded to three others, forming a hexagonal array in a plane, leaving one electron free per carbon atom. This contributes to its electrical conductivity. Thus, this statement is correct.

When metals react with acids, a displacement reaction occurs, resulting in the formation of a salt and hydrogen gas. For instance, when Sodium (Na) reacts with hydrochloric acid (HCl), sodium chloride (NaCl) and hydrogen gas (H2) are produced. Non-metals do not react with acids because they inherently accept electrons, making it impossible for them to donate electrons to the hydrogen ions of the acid.

Malleability allows metals to be hammered or pressed into thin sheets without breaking, like a piece of dough being flattened without tearing. Ductility allows metals to be drawn into thin wires, like stretching a piece of Play-Doh without snapping. Metals can be stretched into long, thin forms due to their ductility.

Statement A is false. The modern periodic table contains 118 officially recognized elements, not 114. IUPAC confirmed elements 113, 115, 117 and 118, completing the seventh period. Statement B is also false. An ore is a naturally occurring material from which economically valuable minerals or metals can be extracted; an ore itself is not necessarily a metal.

Anthracite is the highest grade of coal with the highest carbon content, exceeding 86%. It is the most metamorphosed form of coal, containing minimal moisture and volatile matter, making it a hard, dense coal. It has the highest calorific value, around 35 megajoules per kilogram, and is rare, comprising less than 2% of the coal reserves in the U.S. and is mostly found in northeastern Pennsylvania.

Galvanization is the process in which a protective layer of zinc is applied to the iron to protect it from rusting. Zinc is used in the galvanization process because zinc forms a protective oxide layer on its surface when it reacts with oxygen. This protective layer of zinc oxide acts as a physical barrier to prevent the oxidising of iron by oxygen.

Aluminium oxide (Al2O3) is amphoteric in nature. While most metal oxides are basic, aluminium oxide exhibits amphoteric behavior. This means it can react with both acids and bases: with acids, Al2O3 acts as a base and accepts protons (H+), forming a salt and water; with bases, Al2O3 acts as an acid and donates protons (H+), forming a salt and water.

Quick Silver refers to Mercury (Hg). Mercury is a unique metal that is liquid at room temperature, known for its silvery appearance and high density. Mercury has various applications, including thermometers, barometers, and in some industrial processes.

Humphry Davy, an English chemist, discovered and isolated the highly reactive alkali metals sodium and potassium by using the method of electrolysis. He passed electric current through molten compounds to decompose them into their elements. Sodium was obtained from molten NaOH and potassium from molten KOH. In the early 19th century, Davy employed electrolysis to break down molten salts into their constituent elements.

Amphoteric oxides are oxides that can react with both acids and bases. For example, Aluminium oxide (Al2O3). Aluminium oxide reacts with acids like hydrochloric acid (HCl) and bases like sodium hydroxide (NaOH), to form salt and water. Al2O3 + 6HCl → 2AlCl3 + 3H2O (Salt); Al2O3 + 2NaOH → 2NaAlO2 + H2O (Salt).