Tag: chemical bonding and structure

Questions Related to chemical bonding and structure

Consider the following statements:
(a) Mass is not affected by temperature and pressure.
(b) Plasma contains ionised gases.
(c) Alloys are homogenous mixtures.
(d) Solution is a heterogeneous mixture.
Which of the above statements are correct?

  1. (a), (b) and (c)

  2. (b) and (c)

  3. (a), (c) and (d)

  4. (a) and (d)


Correct Option: A
Explanation:

a. An increasing or decreasing temperature doesn't affect mass. Mass is the amount of matter in an object whereas temperature is the human sense of kinetic energy of matter. Thermal energy is very, very, very small, so no, it is not measurable as mass.

b. Plasma is the fourth state of matter. Plasma is an ionized gas, a gas into which sufficient energy is provided to free electrons from atoms or molecules and to allow both species, ions and electrons, to coexist.

c. An alloy is a homogeneous mixture of 2 or more metals or metal with 2 or more semi-metals.

d. It is homogeneous because the additions take place in the liquid state, so the atoms mingle with each other and mix thoroughly.

An alloy is a material composed of two or more metals or a metal and a nonmetal. 

  1. True

  2. False


Correct Option: A
Explanation:

An alloy is a material composed of two or more metals or a metal and a nonmetal. An alloy may be a solid solution of the elements (a single phase), a mixture of metallic phases (two or more solutions) or an intermetallic compound with no distinct boundary between the phases. Solid solution alloys give a single solid phase microstructure, while partial solutions exhibit two or more phases that may or may not be homogeneous in distribution, depending on the thermal (heat treatment) history of the material. An inter-metallic compound has one other alloy or pure metal embedded within another pure metal.

The primary metal in an alloy is called:

  1. base

  2. metalloid

  3. crystal

  4. none of above


Correct Option: A
Explanation:

The term alloy is used to describe a mixture of atoms in which the primary constituent is a metal. The primary metal is called the base, the matrix, or the solvent.

Statement 1 : A mixture of pure metals is called an alloy. The melting point of an alloy will be lower than either of the component metal.
Statement 2 : The new bonds are weaker.

  1. Both Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1

  2. Both Statement 1 and Statement 2 are correct and Statement 2 is not the correct explanation of Statement 1

  3. Statement 1 is correct but Statement 2 is not correct

  4. Statement 1 is not correct but Statement 2 is  correct

  5. Both the Statement 1 and Statement 2 are not correct


Correct Option: A
Explanation:

Both Statement 1 and Statement 2 is correct and Statement 2 is the correct explanation of Statement 1.


A mixture of pure metals is called an alloy. The melting point of an alloy will be lower than either of the component metal because the new bonds are weaker.

Hence, the correct option is A.

Tinned iron sheets are used for making boxes for fruits, oils, vegetables etc.

  1. True

  2. False


Correct Option: A
Explanation:

Tinning is the process of thinly coating sheets of wroughtiron or steel with tin, and the resulting product is known as tinplate. While once more widely used, the primary use of tinplate now is the manufacture of tin cans. Formerly, tinplate was used for cheap pots, pans and other holloware. It has an extremely beautiful metallic luster as well as excellent properties in corrosion resistance, solderability, and weldability. 

So it's true.

Tin is used for making fusible alloys.

  1. True

  2. False


Correct Option: A
Explanation:

fusible alloy is a metal alloy capable of being easily fused, i.e. easily meltable, at relatively low temperatures. The most widely used fusible alloys contain high percentages of bismuth, combined with lead, tin, cadmium, indium and other metals. Bismuth has an impact on the melting point, as well as the growth and shrinkage characteristics of the alloys.

The main component of bronze is:

  1. cobalt

  2. copper

  3. tin

  4. aluminium


Correct Option: B
Explanation:

Bronze is an alloy consisting primarily of copper, commonly with about 12% tin and often with the addition of other metals (such as aluminium, manganese, nickel or zinc) and sometimes non-metals or metalloids such as arsenic, phosphorus or silicon.

$SiO _2$ (Silica) occurs in the form of:

  1. sand

  2. quartz

  3. opal

  4. all of these


Correct Option: D
Explanation:

Silica also known as silicon dioxide. It is found in nature as quartz, sand or opal. Silica more so than almost any material exists in many crystalline forms called polymorphs. Silica in the form of sand is used as ingredient in sand casting.

_________ cannot be readily separated by physical means.

  1. Mixtures

  2. Metals

  3. Alloys

  4. Non-metals


Correct Option: C
Explanation:

Alloys are metallic materials consisting of two or more elements combined in such a way that they cannot be readily separated by physical means. More than 90% of metals used are in the form of alloys.

Alloys are the examples of mixtures of:

  1. solid-in-gas

  2. gas-in-solid

  3. gas-in-gas

  4. solid-in-solid


Correct Option: D
Explanation:

An alloy is a mixture of two or more metals. Thusit is solid in solid.