Chemistry Test

A liquid containing at least 100 per cent of pure ethanol by weight is called absolute alcohol.

During dehydration, the lose of electrolyte (sodium chloride) takes place from the body.

Diamond is an allotropic form of carbon. It contains carbon only.

The fibre least prone to catch fire is cotton.

Oxidation is a chemical process as it involves the formation of new compounds with new properties.

Comparison of the substances in the gaseous phase is easy due to large distances between the particles in this case.

Due to very high melting point of tungsten it can withstand very high temperature inside the bulb without burning. So filament of the bulb is made of tungsten.

A carbohydrate is an organic compound with the empirical formula C_m(H₂O)_n (where m could be different from n); that is, consists only of carbon, hydrogen, and oxygen, with a hydrogen: oxygen atom ratio of 2 : 1.

In addition to iron, carbon, and chromium, modern stainless steel may also contain other elements, such as nickel, niobium, molybdenum, and titanium.

Anthracite is a hard, compact variety of mineral coal that has a high luster. It has the highest carbon count, the fewest impurities, the highest calorific content of all types of coals, which also include bituminous coal and lignite.

Lactic acid is found primarily in sour milk products, such as curd.

Chlorine is one of the most commonly used disinfectants for water disinfection. Chlorine can be applied for the deactivation of most microorganisms and it is relatively cheap.

Tin bonds readily to iron and is used for coating lead or zinc and steel to prevent corrosion.

Hydrogen is a chemical element. It is the simplest atom in the Universe. On a periodic table of the elements, hydrogen is on the top row, usually either on the left or on its own above the transition metals.

Growth of harmful bacteria increases with the presence of water. So dehydration of fruits is done before tinning them for food.

Graphite is an allotrope (a different structural form) of carbon (so is diamond), but unlike diamond, graphite can conduct electricity. The reason is that graphite consists of flat hexagons, all liked together in a flat plane. The carbons in the hexagons have delocalized pi bonding (pi bonds, along with a sigma bond, make up a double bond) which allows electrons to easily move from atom to atom.

The Silicates are by far the largest group of minerals present rocks. Chemically, these minerals contain varying amounts of silicon and oxygen. It is easy to distinguish silicate minerals from other groups, but difficult to identify individual minerals within this group. None are completely opaque. Most are light in weight. The construction component of all silicates is the tetrahedron. A tetrahedon is a chemical structure where a silicon atom is joined by four oxygen atoms (SiO₄).

Carbon forms more compounds than any other metal as it has 4 valence, electrons, allowing for up to 4 atoms to be attached to it.

Nitrogen is an essential component for plant growth. Nitrogen deficiency most often results in stunted growth, slow growth, and chlorosis. Nitrogen deficient plants will also exhibit a purple appearance on the stems, petioles and underside of leaves from an accumulation of anthocyanin pigements.

Because helium is inert in nature and does not react with any component present in air.

Powder color contains an exclusive base ingredient which is the key to the successful development of latent prints. So this powder is used for developing finger prints on a multicoloured surface.

Atomic number = number of protons = number of electrons

Solder is a fusible metal alloy used to join together metal workpieces and having a melting point below that of the workpiece. It has lowest melting point of the given substances.

Sublimation (phase transition) is the change from solid to gas without entering liquid phase. Substances which undergo evaporation without going into liquid phase are purified by this method.