Tag: chemistry

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Questions Related to chemistry

Multiple choice metals alloys and crystals chemistry elements and compounds alloys and their properties chemical bonding and structure

Which of the following properties of elements can be modified by the formation of alloys?

  1. Resistance to corrosion

  2. Toughness

  3. Malleability & ductility

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Alloys are used in some applications, where their properties are superior to those of the pure component elements, for a given application. This can include improvement in corrosion resistance (like stainless steel), toughness (like carbon-iron alloys) and malleability-ductility (like wrought iron).

Multiple choice chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

Which of the following methods can be used for the preparation of alloys?

  1. Melting a mixture of metals

  2. Simultaneous eletrolytic deposition of metals

  3. By mixing the aqeous solutions of the metal salts

  4. Both 1 and 2
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Alloys can either be produced by melting a mixture of metals or simultaneous eletrolytic deposition of metals. This is because alloys are interstitial compounds, and have one atom of a metal inside the solid structure of another atom. This requires mixing in an efficient way, and not just normal physical conditions. 

Multiple choice chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

Raney Nickel is finely divided nickel obtained by digesting alloys of $Ni/Al $ over $NaOH$.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Raney nickel is a fine-grained solid composed mostly of nickel derived from a nickel aluminum alloy
The alloy is treated with a concentrated solution of sodium hydroxide. The simplified leaching reaction is:
$2Al + 2NaOH + 6 H _2O \rightarrow  2 Na[Al{(OH)} _4] + 3 H _2$
After this process, leaching is done to form raney nickel which is powder and spongey.
Given statement is true.
Multiple choice chemistry elements and compounds alloys and their properties metals, alloys and crystals 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)
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

Multiple choice chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

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

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

Multiple choice chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

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. <p>Both Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1</p>

  2. <p>Both Statement 1 and Statement 2 are correct and Statement 2 is not the correct explanation of Statement 1</p>

  3. <p>Statement 1 is correct but Statement 2 is not correct</p>

  4. <p>Statement 1 is not correct but Statement 2 is correct</p>

  5. <p>Both the Statement 1 and Statement 2 are not correct</p>
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

Multiple choice chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

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

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
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.