Tag: chemical bonding and structure

Questions Related to chemical bonding and structure

When items of jewellery made of base metals like copper, iron or nickel are placed in a solution containing a compound of gold, a film of gold is deposited by:

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

  1. cooling to $5$ degree centigrade

  2. adding acid

  3. heating

  4. passing an electric current

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Correct Option: D
Explanation:

Electroplating is the process in which a layer of a metal is deposited on metallic or non-metallic electrode by electrolysis in an electrolytic cell.

When items of jewellery made of base metals like copper, iron or nickel are placed in a solution containing a compound of gold, a film of gold is deposited by the process of electroplating which  requires passing an electric current in it.
Hence option D gives the correct answer.

Which of the following shows both the properties of both metals and non-metals?

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

  1. $\displaystyle F$

  2. $\displaystyle Li$

  3. $\displaystyle Fe$

  4. $\displaystyle He$

  5. $\displaystyle Si$

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Correct Option: E
Explanation:

Silicon is a metalloid, a semimetallic element that is neither a metal nor a nonmetal but has some of the properties or characteristics of the two. A semi-metal in the periodic table, silicon is one of the elements that can't be found in nature in its elemental form. It is also one of the most common elements in nature, accounting for about 28 percent of the earth's crust by mass.

Monel metal is a metallic alloy of copper and nickel with $5$% iron. It is used in making:

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

  1. locks

  2. strong boxes

  3. almirahs

  4. motor parts

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Correct Option: A
Explanation:

Monel is a group of nickel alloys, primarily composed of nickel (up to 67%) and copper, with small amounts of iron, manganese, carbon, and silicon. Stronger than pure nickel, Monel alloys are resistant to corrosion by many agents, including rapidly flowing seawater.

Being stronger than pure nickle Monel metal is used in making locks.
Hence option A is correct answer.

Which of the following is not an alloy containing tin metal?

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

  1. Solder for soldering electrical contacts

  2. Pewter for hardness

  3. Bronze for statues

  4. Brass for articles like bangles and utensils

Show answer
Correct Option: D
Explanation:

 Brass for articles like bangles and utensils.

Brass is an alloy of copper and zinc having molecular formula ${Cu} _{3}{Zn} _{2}$

Which of the following is a steel that is resistant to acids?

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

  1. Nickel alloy steel

  2. Molybdenum steel

  3. Stainless steel

  4. Cobalt alloy steel

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Correct Option: B
Explanation:

Molybdenum can be obtained from the minerals molybdenite, wulfenite and powellite. It is also obtained as a byproduct during tungsten and copper mining and processing. It has one of the highest melting points of all pure elements; however it is not resistant to acids.Hence, molybdenum steel is also not resistant to acids.

Hence option B is correct answer.

In metallurgy of iron, limestone provides flux for removing impurities as slag.

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

  1. True

  2. False

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Correct Option: A
Explanation:

The above statement is true.
In agglomeration and separation of melted or smelted copper it is necessary to introduce iron oxide or limestone as flux to remove the impurities.

During the formation of hydronium ion, water molecule acts as _______.

chemistry chemical bonding and structure coordinate bond types of bonds and properties chemical bond and chemical equation

  1. solvent

  2. donor

  3. acceptor

  4. none of these

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Correct Option: B
Explanation:

During the formation of hydronium ion, water molecule acts as donor.

A coordinate covalent bond is represented by an arrow from donor to acceptor.

chemistry chemical bonding and structure coordinate bond types of bonds and properties chemical bond and chemical equation

  1. True

  2. False

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Correct Option: A
Explanation:

Coordinate covalent bond is represented by an arrow from donor to acceptor.

Eg:NO $[NH _3 \to H]^+$
Coordinate covalent bond means donating a lone pair of electron of one atom to a vacant orbital of another atom.

Compounds having coordinate covalent bonds are:

chemistry chemical bonding and structure coordinate bond types of bonds and properties chemical bond and chemical equation
    • $CO$

  2. $HNO _3$

  3. $NH _4^+$

  4. All of the above

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Correct Option: D
Explanation:

Compounds having coordinate covalent bonds are $CO, HNO _3, NH _4^+$.

Addition of acid to water results in the formation of:

chemistry chemical bonding and structure coordinate bond types of bonds and properties chemical bond and chemical equation

  1. $H _2O$

  2. $H _3O^+$

  3. both A and B

  4. none of the above

Show answer
Correct Option: B
Explanation:

Addition of acid to water results in the formation of $H _3O^+$.

$H^++H _2O \rightarrow H _3O^+$