Chemistry of Metals and Alloys

Red phosphorus is used in safety matches because it is stable and less reactive than white phosphorus. The striking surface contains red phosphorus, which reacts with the match head compounds when rubbed against it. White phosphorus is too dangerous and spontaneously ignites in air.

Mercury is the only metal that forms amalgams (alloys) with other metals at room temperature. This unique property is because mercury is liquid at room temperature and can dissolve many other metals. Amalgams have various applications, including in dentistry and gold extraction.

Gold is the most malleable metal, meaning it can be hammered into extremely thin sheets without breaking. A single gram of gold can be beaten into a sheet covering several square meters. Silver and aluminum are also malleable but not to the same extent as gold, while sodium is too reactive.

“Silver” is the metal that is present in the photo film and the reason for it is that it creates darkness on the film or photo. The developer dissolves the unreacted silver and makes the film or photo stable to light.

A more reactive metal can displace a less reactive metal from its salt solution. Magnesium is more reactive than zinc (higher in reactivity series), so it can displace zinc from zinc sulphate solution. Lead, iron, and mercury are less reactive than zinc.

Active metals like zinc can displace hydrogen from dilute acids because they are more reactive than hydrogen. Zinc reacts with dilute HCl or H2SO4 to form Zn2+ ions and hydrogen gas. Gold, copper, and silver are less reactive than hydrogen.

Gold is a noble metal, meaning it is resistant to corrosion and oxidation. Diamond is not a metal, and steel is an alloy of iron.

Aluminum is used for connecting leads in IC chips due to its excellent conductivity, low cost, and ability to form reliable wire bonds. Silicon and germanium are semiconductors used for the chip substrate, while lead is not used due to toxicity and poor bonding properties.

Lithium chloride is produced by treatment of lithium carbonate with hydrochloric acid. Lithium chloride is mainly used for the production of lithium metal by electrolysis of a LiCl/KCl melt at 600 °C. LiCl is also used as a brazing flux for aluminium in automobile parts. It is used as a desiccant for drying air streams.

This option is correct.

Phosphorus is a nonmetallic element located in Group 15 of the periodic table. It exists in several allotropic forms (white, red, black) and is essential for life, being a component of DNA, RNA, and ATP.

An amphiprotic species is a molecule or ion that can both accept and donate protons. A common example of an amphiprotic metal is  Zinc: In acid: ZnO + 2H+ → Zn²⁺ + H₂O. In base: ZnO + H₂O + 2OH- → [Zn(OH)₄]^2- Almunium: In acid : Al₂O₃ + 3 H₂O + 6 H₃O+(aq) → 2 [Al(H₂O)₆]³⁺(aq) In base: Al₂O₃ + 3 H₂O + 2OH-(aq) → 2 [Al(OH)₄]^-(aq) Lead: In acid : PbO + 2 HCl → PbCl₂ + H₂O In base : PbO + 2 NaOH + H₂O → Na₂[Pb(OH)₄]

Solder, which is primarily composed of lead (or lead-tin alloy), is the standard metal used for joining wires and components in electronic circuit boards due to its low melting point and good conductivity. While silver and gold are excellent conductors, they are too expensive for routine soldering use, and mercury is a liquid at room temperature making it impractical for permanent connections.

Magnesium is the only metal among these options that is commercially extracted from seawater on a large scale. The process involves electrolysis of magnesium chloride obtained from seawater, where magnesium is present at about 1.3 g/kg. Magnesium compounds are abundant in ocean water, while potassium comes primarily from mineral deposits (sylvite), aluminium from bauxite ore, and beryllium from bertrandite and beryl minerals.

A. Copper has very good anti-corrosive property and is used for making wires used in electrical industry and for water and steam pipes. B. German silver contains Cu 25-30%, Zn 25-30% and Ni 40–50%. C. Zinc dust is used as a reducing agent in the manufacture of dye-stuffs, paints, etc. and in a several organic and inorganic synthesis reactions.