Chemistry of Metals and Alloys

The reference electrode is made from Hg₂CI₂.

Magnesium burns brightly in oxygen to form a metal oxide called magnesium oxide with the chemical formula MgO. Magnesium is a chemical that burns with a white flame. The colours are produced by the redox reaction and depend on what kind of salt or metal is burning. To produce very bright light the creator of the fireworks will use magnesium, aluminium and titanium.

Silicon is the seventh most abundant element in the universe and the second most abundant element in the Earth's crust. Silicon with carbon atoms forms silicon carbide that is next to diamond in hardness and is therefore used for making tools used in grinding.

Pure silver is the best conductor of heat and electricity of all the known metals. So, it is sometimes used in making solder, electrical contacts and printed circuit boards. Silver actually conducts electricity more efficiently than copper.

Of all the metals, untarnished silver is the best reflector of light. As a result it was used in ancient times to make mirrors. Unfortunately, silver tarnishes very easily and quickly.

Silicon carbide also known as carborundum is a compound of silicon and carbon with chemical formula SiC. In manufacturing, it is used for its hardness in abrasive machining processes, such as grinding, honing, water jet cutting and sandblasting.

Chrome orange also known as chrome red is an orange pigment, which consists of lead (II) chromate and lead (II) oxide. Chrome orange can be made by precipitating lead (II) together with chromate in a basic solution or by treating chrome yellow with dye. Chrome yellow is a kind of yellow powder and is the isomorphous crystal mixture of lead chromate and lead sulphate.

The metals Iike iron, lead and copper do not burn in air. Instead they get covered with an oxide layer that is insoluble in water. When copper oxidizes it forms a very thin layer of copper oxide on the outer surface of the copper that further protects the surface from oxidation. This layer is greenish in colour and is called patina.

Copper turns green, when exposed to air due to the formation of a protective layer of copper carbonate. This protective green coating is called verdigris.

All metals are sonorous except mercury and lead. Mercury occurs in liquid state so lead is the only non sonorous metal occurring in solid state and thus exhibiting the properties of non metals.

Copper turns green when exposed to air due to the formation of a protective layer of copper carbonate called verdigris. Verdigris is a green coating or patina formed, when an alloy of copper, bronze or brass is weathered and exposed to the atmosphere or water over a long period of time. The colour of verdigris varies from shades of blue to shades of green. The simple composition of verdigris is copper carbonate and copper hydroxide,  but if verdigris is being formed at the seashore or somewhere near the sea it consists of copper chloride.

Alnico is a powerful permanent magnet alloy containing iron, nickel and aluminium. Aluminium nickel cobalt (AlNiCo) magnet alloy exhibits excellent temperature stability.

Bell metal is an alloy and consists of Cu = 80%, Sn = 20%. Wood metal consists of Bi = 50%, Pb = 25%, Sn = 12.5% & Cd = 12.5% and is used in the making of automatic sprinkles as it melts in hot water (m.p.= 68 oC). Duralumin is used in the manufacturing of aeroplane parts and consists of Al = 95.5%, Cu = 4%, Mg = 0.5% and Mn = 0.5%.

Gold leaf electroscope consists of (1) brass disc (2) rubber stopper (3) brass rod (4) gold leaf. So 3^rd option i.e. metallic rubber is not present in the gold leaf electroscope.

Gallium is a chemical element with symbol Ga and atomic number 31. Elemental gallium does not occur in nature but as gallium compounds in trace amounts in bauxite and zinc ores.