The correct answer is option D) Henry Moseley.

Henry Moseley was an English physicist who is known for his experiments in X-ray spectroscopy. He discovered the relationship between the atomic number of an element and its X-ray spectrum, which led to the understanding of the fundamental importance of atomic number.

Moseley’s work confirmed the validity of the periodic table, as it showed that elements with similar properties have similar atomic numbers, and therefore fit into a repeating pattern. This discovery is often referred to as Moseley’s Law, which states that the properties of elements are a periodic function of their atomic number.

A) Johann Wolfgang Döbereiner was a German chemist who is known for his discovery of triads, groups of three elements with similar properties.

B) John Newlands was an English chemist who is known for his law of octaves, which states that every eighth element in the periodic table has similar properties to the first.

C) Dmitri Ivanovich Mendeleev was a Russian chemist who is best known for creating the periodic table of elements, organizing the elements by their atomic number and chemical properties in a way that showed their periodic relationships.

D) Henry Moseley was an English physicist who is known for his experiments in X-ray spectroscopy and his discovery of the relationship between the atomic number of an element and its X-ray spectrum, leading to the understanding of the fundamental importance of atomic number in the periodic table of elements.

The correct answer is D) Henry Moseley.

The correct answer is A) Due to an increase in nuclear charge

The reason for the decrease in atomic radius as one moves from left to right along a period in the periodic table is due to an increase in nuclear charge. This increase in nuclear charge pulls the electrons closer to the nucleus, causing the atomic radius to decrease.

A) Due to an increase in nuclear charge: As you move from left to right along a period in the periodic table, the number of protons in the nucleus increases. This increase in the positive charge of the nucleus leads to a decrease in the atomic radius as the negatively charged electrons are pulled closer to the nucleus.

B) Due to a decrease in nuclear charge: This option is incorrect as the nuclear charge increases as we move from left to right along a period.

C) Due to the addition of new shells: As you move from left to right along a period in the periodic table, new electron shells are added. This increases the number of electrons and thus the size of the atom. But, the increase in the positive charge of the nucleus pulls the electrons closer to the nucleus leading to a decrease in the atomic radius.

D) Both A and C: Both the increase in the positive charge of the nucleus and the addition of new electron shells contribute to the decrease in the atomic radius as we move from left to right along a period in the periodic table.

The correct answer is option A) Due to an increase in nuclear charge

The correct answer is B) Dmitri lvanovich Mendeléev

He was a Russian chemist who is credited with the development of the periodic law and the creation of the periodic table of elements. He arranged the elements in order of increasing atomic mass and noticed that elements with similar properties fell into the same vertical column or group.

A) Johann Wolfgang Döbereiner – He was a German chemist who first recognized triads, or groups of three elements that had similar properties. This was an early observation of the periodic law, but it was not developed into a full-fledged theory.

B) Dmitri lvanovich Mendeléev – He was a Russian chemist who is credited with the development of the periodic law and the creation of the periodic table of elements. He arranged the elements in order of increasing atomic mass and noticed that elements with similar properties fell into the same vertical column or group.

C) John Newlands – He was an English chemist who arranged the elements in order of increasing atomic mass and noticed repeating patterns, similar to Mendeleev’s observations. However, his law of octaves was not widely accepted at the time and he is often overshadowed by Mendeleev’s work.

D) Albert Einstein – He was a German physicist who made many contributions to the fields of physics and mathematics. He is not known for the discovery or development of the periodic law.

The correct answer is option B) Dmitri lvanovich Mendeléev

The correct answer is B) Sodium acetate

It is a salt of acetic acid and sodium. It is commonly used as a buffer solution in the lab and also in food industry.

A) Sodium chloride – It is a salt commonly known as table salt. It is composed of positively charged sodium cations and negatively charged chloride anions.

B) Sodium acetate – It is a salt of acetic acid and sodium. It is commonly used as a buffer solution in the lab and also in food industry.

C) Ammonium nitrate – It is a nitrate salt that is used as a high-nitrogen fertilizer, but also as an explosive in mining and construction.

D) None of the above – This option is a placeholder for any option that is not relevant to the question.

The correct answer is option B) Sodium acetate

The correct answer is A) Acetic acid

Ethanoic acid is commonly referred to as Acetic acid. It is a colorless liquid organic acid with a pungent and sour taste.

A) Acetic acid: Ethanoic acid is commonly referred to as Acetic acid. It is a colorless liquid organic acid with a pungent and sour taste.

B) Sulphuric acid: Sulphuric acid is a strong and highly corrosive inorganic acid, not Ethanoic acid.

C) Sodium Ethoxide: Sodium Ethoxide is a sodium alkoxide salt, not Ethanoic acid.

D) Ethyne: Ethyne is a colorless, highly flammable and explosive gas also known as acetylene, not Ethanoic acid.

The correct answer is option A) Acetic acid

The correct answer is option C) Ethanol

Ethanol is commonly known as alcohol and is used in medicines such as tincture iodine, cough syrups, and many tonics.

• Propanol: is a type of alcohol with a molecular formula of C3H8O. It is used as a solvent, in the manufacture of personal care and cleaning products, and as an intermediate in the production of other chemicals.
• Butane: is a colorless and odorless gas that is used as a fuel for heating, cooking, and in portable stoves. It has a molecular formula of C4H10.
• Ethanol: is a colorless and volatile liquid that is used as a solvent, in the production of personal care and cleaning products, and as an alternative fuel for vehicles. It has a molecular formula of C2H5OH.
• Methanol: is a colorless, volatile liquid that is used as a solvent, fuel, and antifreeze in the radiator. It has a molecular formula of CH3OH.

The correct answer is C) Ethanol

The correct answer is option D) All of the above

This statement is false. All the other statements are true. Heteroatoms are atoms of elements other than carbon and hydrogen in a molecule. The presence of heteroatoms in a molecule can significantly impact its properties, making it different from a corresponding hydrocarbon. Chlorine and oxygen are examples of heteroatoms that can be present in organic compounds.

A) It is formed by the replacement of one or more hydrogen atoms by another element – This statement is true. Heteroatoms are elements other than carbon and hydrogen that are present in organic compounds, typically by replacing one or more hydrogen atoms in a hydrocarbon molecule.

B) It gives some specific properties to the compound so formed – This statement is true. The presence of heteroatoms in an organic compound can significantly impact its properties, giving it specific and distinct characteristics that distinguish it from a corresponding hydrocarbon.

C) Chlorine and Oxygen are examples of heteroatoms – This statement is true. Chlorine and oxygen are two common heteroatoms that are present in many organic compounds and give them specific properties.

D) All of the above – This statement is false, as it includes a false statement, that all the above statements are true.

The correct answer is D) All of the above

The correct answer is option B) Structural isomers

Compounds with identical molecular formulas but different structures are called structural isomers. Structural isomers are compounds that have the same molecular formula but different arrangements of atoms in their molecules, leading to different molecular structures. These compounds have distinct physical and chemical properties and are not interconvertible under normal laboratory conditions.

A) Tetravalent compounds – Tetravalent refers to an element or an atom that has a valence of 4, meaning it can form 4 bonds with other atoms. This term does not refer to a specific type of compound.

B) Structural isomers – Structural isomers are compounds with the same molecular formula but different arrangements of atoms in their molecules, leading to different molecular structures. These compounds have distinct physical and chemical properties and are not interconvertible under normal laboratory conditions.

C) Covalent compounds – Covalent compounds are compounds formed by the sharing of electrons between two or more atoms. While structural isomers can be covalently bonded, the term covalent compounds does not specifically refer to structural isomers.

D) None of the above – This is not correct. Option B (Structural isomers) is the correct answer.

The correct answer is B) Structural isomers

The correct answer option is A) Ability to form bonds with other atoms, leading to large chains of molecules.

Catenation refers to the ability of carbon to form bonds with other atoms, leading to the formation of large chains of molecules.

This property of carbon is one of the most important, and it makes carbon a versatile element that can form a wide range of organic compounds, including hydrocarbons, carbohydrates, proteins, and more.

This ability of carbon to form long chains is due to the presence of four electrons in its outermost shell, which makes it possible for carbon to bond with up to four other atoms.

A) Ability to form bonds with other atoms, leading to large chains of molecules – This is the correct definition of catenation. Catenation refers to the ability of carbon to form bonds with other atoms, leading to the formation of large chains of molecules.

B) Ability to conduct electricity – This is not the definition of catenation. Carbon is not a good conductor of electricity, but it does have the property of catenation.

C) Ability to have different types of allotropes – This is not the definition of catenation. Carbon does have the property of forming different allotropes, but this is not what catenation refers to.

D) All of the above – This is not correct. Only the first option is the definition of catenation.

The correct answer is A) Ability to form bonds with other atoms, leading to large chains of molecules.

The correct answer is  option C) Only I and II

Graphite is a form of carbon, which is true (I). Each carbon atom in graphite is bonded to three other carbon atoms in the same plane, giving it a hexagonal structure, which is also true (II). Graphite, however, is not one of the hardest known substances, so III is false.

A) Only I – This statement is partially correct. Graphite is a form of carbon, but not all the other statements are true.

B) Only III – This statement is incorrect. Graphite is not one of the hardest known substances.

C) Only I and II – This statement is correct. Graphite is a form of carbon (I) and each carbon atom in graphite is bonded to three other carbon atoms in the same plane, giving it a hexagonal structure (II).

D) Only II and III – This statement is partially correct. Graphite has a hexagonal structure, where each carbon atom is bonded to three other carbon atoms in the same plane (II), but it is not one of the hardest known substances (III).

The correct answer is C) Only I and II