Metallurgy, Metals, Non-Metals & Alloy RRB PYQ

5, 6, 7 or 8 is the correct answer, because non-metals generally have 5-8 electrons in their outermost (valence) shell. Since their valence shell is nearly filled, non-metals usually gain or share electrons to achieve a stable octet configuration. Electronic configurations of some non-metals are: Oxygen 2,6; Fluorine 2,7; Sulphur 2,8,6; Chlorine 2,8,7.

Silver is the best conductor of electricity due to its high electrical conductivity. It allows electrons to move more freely than other materials, making it the most efficient at conducting electricity. Although copper and gold are also excellent conductors, silver surpasses them. Rubber, in contrast, is an insulator, not a conductor.

Gangue refers to the unwanted impurities that are naturally present in an ore. These impurities do not contain the desired metal and should be removed during the ore refining process. Wrought is associated with wrought iron, which is a processed form of iron. Spongy refers to a texture of some metals but not related to ore impurities. Hardness of ore tells about the ore's physical property, not its impurities.

Diamond is NOT a combined form of carbon because diamond is an allotrope (free/elemental form) of carbon, not a compound. Chalk and marble contain carbon in combined form mainly as calcium carbonate (CaCO3), so they are carbon compounds. Dolomite contains carbon in combined form as calcium magnesium carbonate, CaMg(CO3)2, so it is also a carbon compound.

Calcination, used in metallurgy, specifically describes the formation of metal oxides by heating carbonate ores. Calcination is the process of heating an ore in the absence or limited supply of air to bring about thermal decomposition or remove volatile impurities. The primary purpose is to convert carbonate ores into oxides, which are easier to reduce to metals.

Equal quantities of both alloys are mixed. Alloy X = 5:2, Total quantity = 5+2 = 7 units...(i). Alloy Y = 5:7, Total quantity = 5+7 = 12 units...(ii). Since equal quantities are mixed, (i)x12 + (ii)x7. Alloy X = 60:24, Alloy Y = 35:49, so Alloy Z = 95:73.

Sodium is a very reactive metal, especially with oxygen and water. When exposed to air, sodium quickly forms a white layer called sodium oxide. When sodium comes into contact with water, it reacts strongly, producing sodium hydroxide and hydrogen gas. This reaction is so intense that it often creates flames. To keep sodium safe, it is usually stored in oil to prevent it from touching air or water.

Bromine (Br2) is the only non-metal that exists as a liquid at room temperature. It is a reddish-brown, volatile liquid with a strong odor and evaporates easily to form a toxic vapor. Chlorine (Cl2) occurs as a gas at room temperature, while Fluorine (F2) is a gas at room temperature. Sulfur (S) exists as a solid at room temperature.

Coke is a strong reducing agent due to its high carbon content and reactivity. During the smelting process in metallurgy, coke reacts with metal oxides (like iron oxide) and removes oxygen, converting them into their pure metal form.

An alloy is considered a mixture even though it cannot be separated by physical methods as it shows the properties of its constituents and can have variable composition. The proportions of the constituent elements in an alloy can be varied within certain limits. An alloy exhibits the characteristic properties of the metals from which it is made. While typical mixtures can often be separated by simple physical methods like filtration or evaporation, alloys require more complex processes.