Practice MCQ Questions and answers on Chemistry-GK

Silicon is used in Solar energy devices, Semiconductors and transistors.

Xenon can form compounds.

A vulcanized flexible tyre rubber contains about 3 –5% of sulphur whereas hard rubber (ebonite) contains about 32% of sulphur. The stiffness of vulcanized rubber depends on the amount of sulphur added.

A magnetic alloy is a combination of various metals from the periodic table that contains at least one of the three main magnetic elements: iron (Fe), nickel (Ni), and cobalt (Co). Such an alloy must contain but is not limited to one or more of these metals. Magnetic alloys have become common, especially in the form of steel (iron and carbon) alnico (iron, nickel, cobalt, and aluminum,) and permalloy (iron and nickel.) The strongest magnetic element is iron, which allows items made out of these alloys to attract to magnets.

In its reaction with silver nitrate, acetylene shows acidic property because H atoms are replaced by Silver metal atoms.

Yellow cake, an item of smuggling across border, is Uranium oxide. Uranium oxide smuggled across border as yellow cake. Enriched uranium can be used in making illegal nuclear explosive that is dangerous to humanity.

The transuranium elements (also known as transuranic elements) are the chemical elements with atomic numbers greater than 92, which is the atomic number of uranium. All of these elements are unstable and decay radioactively into other elements.

Zirconium is non-radioactive. It is a chemical element with the symbol Zr, atomic number 40 and atomic mass of 91.224. The name of zirconium is taken from the mineral zircon, the most important source of zirconium. It is a lustrous, grey-white, strong transition metal that resembles titanium. Zirconium is mainly used as a refractory and opacifier, although minor amounts are used as alloying agent for its strong resistance to corrosion.

Radiocarbon dating (usually referred to as simply carbon dating) is a radiometric dating method that uses the naturally occurring radioisotope carbon-14 (14C) to estimate the age of carbon-bearing materials up to about 58,000 to 62,000 years. Raw, i.e., uncalibrated, radiocarbon ages are usually reported in radiocarbon years “Before Present” (BP), with “present” defined as CE 1950. Such raw ages can be calibrated to give calendar dates. One of the most frequent uses of radiocarbon dating is to estimate the age of organic remains from archaeological sites.

Nickel silver, also known as German silver, Argentan, new silver, nickel brass, albata, alpacca, or electrum, is a copper alloy with nickel and often zinc. The usual formulation is 60% copper, 20% nickel and 20% zinc. Nickel silver is named for its silvery appearance, but it contains no elemental silver unless plated. The name “German silver” refers to its development by 19th-century German metalworkers in imitation of the Chinese alloy known as paktong. Nickel silver first became popular as a base metal for silver-plated cutlery and other silverware, notably the electroplated wares called EPNS (electro-plated nickel silver). It is used in zippers, better-quality keys, costume jewellery, for making musical instruments (e.g., cymbals, saxophones), and is preferred for the track in electrically powered model railway layouts, as its oxide is conductive. It is widely used in the production of coins.