MCQ On Some Basic Concepts of Chemistry: Introduction & Explanation

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Chemistry connects various subjects such as geology, environmental science, biology, and physics. The matter is a core fundamental concept of Chemistry that can be understood as a substance that has inertia and occupies physical space. There are three states of matter: solid, gas, and liquid. There are five basic chemical laws that govern the combination of elements. These are

Law of Conservation of Mass: The law states that in a chemical reaction, the mass of the reactants and products will always stay equal.
Law of Definite Proportions: The law states that each chemical compound contains a constant and fixed proportion of the mass of the elements it constitutes.
Law of Multiple Proportions: The law deals with the rules of stoichiometry that was formed by John Dalton.
Gay Lussac’s Law of Gaseous Volumes: The law was devised in 1808 but was properly explained by Avogadro.
Avogadro Law: The law states that when the pressure and temperature conditions remain the same, equal volume gases contain the same molecules in number.

Ques 1. What is the chemical formula of lime?

CaCO
Ca(HCO₃)
CaO
Ca(OH)₂

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Ans: d. Ca(OH)₂

Explanation: On the reaction of CaO which is Quick lime with water, Ca(OH)₂is produced which is called Lime Water.

CaO + H₂O → Ca(OH)₂

Lime water is a clear and colorless aqueous solution and is used in the detection of carbon dioxide gas. Calcium hydroxide is the chemical name of Lime Water. When the carbon dioxide is present in the mixture it reacts with lime water to form white calcium carbonate that is insoluble and changes the limewater into a milky solution.

Ques 2. Among the following options, which is the ore of Iron?

Malachite
Siderite
Bauxite
Anglesite

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Ans: b. Siderite

Explanation: Siderite is a mineral that occurs in clay, coal, sedimentary deposits and wastes rocks, etc. It is an ore of iron and is used in the production of steel. Other important ores of Iron are Limonite, Hematite, Goethite, Magnetite, etc.

Ques 3. Law of Multiple Proportions was given by:

Joseph Proust
Gay Lussac
Avogadro
John Dalton

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Ans: d. John Dalton

Explanation: The law of multiple proportions was given by John Dalton and is thus also known as Dalton’s Law. The law states that when any two elements are combined to form more than one compound, the weight of one element when combined with a fixed weight of the other elements that are in a ratio of small whole numbers.

Ques 4. Green Vitriol is chemically known as:

Ferric Phosphate
Ferrous Sulphate
Ferric Hydroxide
Ferric Oxide

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Ans: b Ferrous Sulphate

Explanation: Green Vitriol, a blue-green heptahydrate, is used for the treatment of iron deficiency. It helps the body to make healthy blood cells which transports oxygen to various body parts. The deficiency of iron in the human body can lead to anemia. Chemically, it can be referred to as Ferrous Sulphate or Iron (II) Sulphate.

Ferrous Sulphate is found in various hydration states that exist in nature. The formula for the compound can be represented as FeSO4.7H2O.

Ques 5. The sharp flavor is soft drinks is caused by the presence of which of the following acid?

Nitric Acid
Boric Acid
Hydrofluoric Acid
Phosphoric Acid

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Ans: d. Phosphoric Acid

Explanation: Phosphoric Acid is a crystalline liquid that is odorless as well as colorless. It helps in stopping the increase of bacteria which may multiply in sugary liquids. It can cause weakness in the bones if consumed in high amounts. Phosphoric Acid is also used in soaps, dyes, fertilizers, etc. Excessive consumption of phosphoric acid is very harmful for the health, especially of people with kidney problems.

Ques 6. Heavy Water has a molecular weight of:

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Ans: b. 20

Explanation: Heavy water consists of 2 atoms of hydrogen and a single atom of oxygen. The main difference between light and heavy water is the isotope of hydrogen. In light water, both the hydrogens atoms are hydrogen-1 isotope and in heavy water, the hydrogen atoms present are hydrogen-2 isotope. Heavy water is chemically named as deuterium oxide. It is used as a moderator in nuclear reactors.

Ques 7. In Buck- Minster Fullerene, how many atoms of Carbon are present?

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Ans: c. 60

Explanation: The Buck-Minster Fullerene, also known as the C60 compound, consists of 60 carbon atoms that are linked together to form a cage-like structure that is hollow. In this compound, each carbon atom is bonded by three bonds. This allotrope of carbon is a very good conductor of electricity and is extremely strong in nature.

Read More: Alcohols, Phenols and Ethers

Ques 8. Who discovered electrons?

Rutherford
James Chadwick
J.J. Thomson
John Dalton

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Ans: c. J.J. Thomson

Explanation: J.J. Thomson performed several experiments on cathode rays and accidentally electrons were discovered. The performed experiment showed that all the atoms are consists of negatively charged electrons. An atom consists of positive and negative charged electrons.

Ques 9. Which method can be used to separate the mixture of alcohol and acetone?

Fractional Distillation
Separating Funnel
Sublimation
Crystallization

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Ans: a. Fractional Distillation

Explanation: Fractional Distillation is a method of separating two liquids that are mixed together having boiling point less than 25K. The mixture of the liquids is heated till a certain point where one liquid starts vaporizing. This method can also be used to purify chemicals and to obtain the components of the mixtures that are to be separated.

Ques 10. Among the following options, which one is not a pure compound?

H₂O₂
O₃
H₂O
Sucrose Solution

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Ans: d. Sucrose Solution

Explanation: Sucrose Solution is a mixture made up of water and sugar. Sugar can be separated from the solution by using the method of crystallization. The solution is a homogeneous solution as sugar is dissolved completely in the water. Sucrose solution can be used to reduce pain in infants and neonates.

Read Also:

Subatomic Particles of an Atom	Lewis Dot Structures	How to write Electronic Configuration?
Molecular Orbital Theory	Shapes of Atomic Orbitals	Covalent Bond
Oxides of Nitrogen	How to find valency?	Emulsions
Decomposition Reaction	Halides	Phosphine

MCQ On Some Basic Concepts of Chemistry: Introduction & Explanation

CBSE CLASS XII Related Questions

1.
How would you account for the following:
Of the d⁴ species, Cr²⁺ is strongly reducing while manganese(III) is strongly oxidising.
Cobalt(II) is stable in aqueous solution but in the presence of complexing reagents it is easily oxidised.
The d¹ configuration is very unstable in ions.

2.
Define the term solution. How many types of solutions are formed? Write briefly about each type with an example.

3.
Discuss briefly giving an example in each case the role of coordination compounds in:
biological systems
medicinal chemistry
analytical chemistry
extraction/ metallurgy of metals

4.
Give the IUPAC names of the following compounds:
(i)CH₃CH(Cl)CH(Br)CH₃
(ii)CHF₂CBrClF
(iii)ClCH₂C≡CCH₂Br
(iv)(CCl3)₃CCl
(v)CH₃C(p-ClC₆H₄)₂CH(Br)CH₃
(vi)(CH₃)₃CCH=CClC₆H₄I-p

5.
Write down the electronic configuration of:
(i) Cr³⁺ (iii) Cu⁺ (v) Co²⁺ (vii) Mn²⁺
(ii) Pm³⁺ (iv) Ce⁴⁺ (vi) Lu²⁺ (viii) Th⁴⁺

6.
The rate constant for the decomposition of hydrocarbons is 2.418 x 10^-5 s^-1 at 546 K. If the energy of activation is 179.9 kJ/mol, what will be the value of pre-exponential factor.

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MCQ On Some Basic Concepts of Chemistry: Introduction & Explanation

CBSE CLASS XII Related Questions

1. How would you account for the following: Of the d4 species, Cr2+ is strongly reducing while manganese(III) is strongly oxidising. Cobalt(II) is stable in aqueous solution but in the presence of complexing reagents it is easily oxidised. The d1 configuration is very unstable in ions.

2. Define the term solution. How many types of solutions are formed? Write briefly about each type with an example.

3. Discuss briefly giving an example in each case the role of coordination compounds in:biological systemsmedicinal chemistryanalytical chemistryextraction/ metallurgy of metals

4. Give the IUPAC names of the following compounds:(i)CH3CH(Cl)CH(Br)CH3(ii)CHF2CBrClF(iii)ClCH2C≡CCH2Br(iv)(CCl3)3CCl(v)CH3C(p-ClC6H4)2CH(Br)CH3(vi)(CH3)3CCH=CClC6H4I-p

5. Write down the electronic configuration of:(i) Cr3+ (iii) Cu+ (v) Co2+ (vii) Mn2+ (ii) Pm3+ (iv) Ce4+ (vi) Lu2+ (viii) Th4+

6. The rate constant for the decomposition of hydrocarbons is 2.418 x 10-5 s-1 at 546 K. If the energy of activation is 179.9 kJ/mol, what will be the value of pre-exponential factor.

Similar Chemistry Concepts

Comments

SUBSCRIBE TO OUR NEWS LETTER

1.
How would you account for the following:
Of the d⁴ species, Cr²⁺ is strongly reducing while manganese(III) is strongly oxidising.
Cobalt(II) is stable in aqueous solution but in the presence of complexing reagents it is easily oxidised.
The d¹ configuration is very unstable in ions.

2.
Define the term solution. How many types of solutions are formed? Write briefly about each type with an example.

3.
Discuss briefly giving an example in each case the role of coordination compounds in:
biological systems
medicinal chemistry
analytical chemistry
extraction/ metallurgy of metals

4.
Give the IUPAC names of the following compounds:
(i)CH₃CH(Cl)CH(Br)CH₃
(ii)CHF₂CBrClF
(iii)ClCH₂C≡CCH₂Br
(iv)(CCl3)₃CCl
(v)CH₃C(p-ClC₆H₄)₂CH(Br)CH₃
(vi)(CH₃)₃CCH=CClC₆H₄I-p

5.
Write down the electronic configuration of:
(i) Cr³⁺ (iii) Cu⁺ (v) Co²⁺ (vii) Mn²⁺
(ii) Pm³⁺ (iv) Ce⁴⁺ (vi) Lu²⁺ (viii) Th⁴⁺

6.
The rate constant for the decomposition of hydrocarbons is 2.418 x 10^-5 s^-1 at 546 K. If the energy of activation is 179.9 kJ/mol, what will be the value of pre-exponential factor.