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Chemistry Test

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Which of the following gives the correct order, in which things flow from the interior of the earth, from top to bottom, when earth is drilled?

  1. Natural gas, oil, water

  2. Oil, natural gas, water

  3. Water, natural gas, oil

  4. Water, oil, natural gas


Correct Option: C
Explanation:

The correct order, in which things flow from the interior of the earth, from top to bottom is water, natural gas and oil. 

Absolute alcohol is

  1. 100% proof

  2. 95% alcohol and 5% water

  3. 200% proof

  4. rectified spirit


Correct Option: A
Explanation:

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

During dehydration, the substance that is usually lost by the body is

  1. sugar

  2. sodium chloride

  3. calcium phosphate

  4. potassium chloride


Correct Option: B
Explanation:

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

Which of the following substances consists of only one element?

  1. Diamond

  2. Glass

  3. Marble

  4. Sand


Correct Option: A
Explanation:

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

The substance that is least prone to catch and spread fire is

  1. nylon

  2. terrycot

  3. cotton

  4. polyester


Correct Option: C
Explanation:

The fibre least prone to catch fire is cotton.

Which of the following is a chemical change?

  1. Evaporation

  2. Precipitation

  3. Dissolution

  4. Oxidation


Correct Option: D
Explanation:

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

It is easier to compare a substance in the gaseous state because the molecules in this state

  1. are small.

  2. are lighter.

  3. have large space between them.

  4. have very less space between them.


Correct Option: C
Explanation:

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

Why is tungsten used in manufacture of electric bulb?

  1. It is cheaper than other metals

  2. It is both durable and economical

  3. It has high milting point

  4. It makes the bulb light brighter


Correct Option: C
Explanation:

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.

Carbohydrates are composed of

  1. Carbon, Hydrogen and Nitrogen

  2. Nitrogen, Carbon and Oxygen

  3. Oxygen, Hydrogen and Nitrogen

  4. Carbon, Hydrogen and Oxygen


Correct Option: D
Explanation:

A carbohydrate is an organic compound with the empirical formula Cm(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.

Stainless steel is an alloy of

  1. iron and nickel

  2. iron, chromium and nickel

  3. iron, chromium and zinc

  4. iron and manganese


Correct Option: B
Explanation:

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

Which of the following forms of coal has the highest carbon content?

  1. Anthracite

  2. Bitumimous coal

  3. Lignite

  4. Peat


Correct Option: A
Explanation:

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.

When milk is converted into curd, the sour taste is due to

  1. acetic acid

  2. citric acid

  3. lactic acid

  4. tartaric acid


Correct Option: C
Explanation:

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

Water for civil supplies is commonly purified by

  1. chlorination

  2. distillation

  3. filtration

  4. decantation


Correct Option: A
Explanation:

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.

The street Kalai Wala gives shining appearance to utensils by rubbing a shining silvery material. What is this material made up of?

  1. Tin

  2. Zinc

  3. Lead

  4. Aluminium


Correct Option: A
Explanation:

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

Which is the lightest element in the universe?

  1. Helium

  2. Hydrogen

  3. Nitrogen

  4. Silicon


Correct Option: B
Explanation:

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.

Dehydration of fruits is done before tinning them for food. This is done

  1. to add nutrients in the fruits

  2. to remove bacteria

  3. to prevent microbial growth

  4. to preserve the essence


Correct Option: C
Explanation:

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

Which is the only non-metal, that is a good conductor of electricity?

  1. Graphite

  2. Phosphorous

  3. Sulphur

  4. Hydrogen


Correct Option: A
Explanation:

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 element present in the largest amount in rocks and minerals is

  1. silicon

  2. carbon

  3. hydrogen

  4. gold


Correct Option: A
Explanation:

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).

The element which forms the largest number of compounds with hydrogen is

  1. oxygen

  2. silicon

  3. carbon

  4. boron


Correct Option: C
Explanation:

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.

For plant growth, the most important compounds are made up of

  1. carbon

  2. nitrogen

  3. sodium

  4. sulphur


Correct Option: B
Explanation:

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.

Helium is preferred to hydrogen in air balloons because it

  1. is cheaper

  2. is less dense

  3. has greater lifting power

  4. does not form an explosive mixture with air


Correct Option: D
Explanation:

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

Powder used for developing finger prints on a multicoloured surface is

  1. manganese dioxide

  2. charcoal

  3. gold dust

  4. fluorescent powder


Correct Option: A
Explanation:

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.

An atom of an element with atomic number 7 will contain

  1. 7 neutrons.

  2. 5 electrons and 2 protons.

  3. 7 protons only.

  4. 7 electrons and 7 protons.


Correct Option: D
Explanation:

Atomic number = number of protons = number of electrons

Which one of the following alloys melts at low temperature?

  1. Solder

  2. Brass

  3. Bronze

  4. German silver


Correct Option: A
Explanation:

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.

The process of purification of a substance which involves evaporation without melting, can be carried out by

  1. crystallisation

  2. distillation

  3. steam distillation

  4. sublimation


Correct Option: D
Explanation:

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.

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