1.
The major portion of natural gas is:
Correct Answer
D. Methane
Explanation
Methane is the major portion of natural gas because it typically makes up around 70-90% of the composition of natural gas. It is the simplest hydrocarbon molecule, consisting of one carbon atom bonded to four hydrogen atoms. Methane is highly flammable and is the main component responsible for the energy content of natural gas. It is also the primary greenhouse gas emitted by human activities, such as the production and use of fossil fuels.
2.
Carbon is likely to bond to other inorganic elements through
Correct Answer
C. Covalent bonds
Explanation
Inorganic compounds are typically formed through covalent bonds. Covalent bonds involve the sharing of electrons between atoms, which allows for the formation of stable compounds. In contrast, ionic bonds involve the transfer of electrons between atoms, and metallic bonds involve the delocalization of electrons in a metal lattice. Since carbon is a nonmetal, it is more likely to form covalent bonds with other elements in inorganic compounds. Therefore, the correct answer is covalent bonds.
3.
Which of the following is an aromatic compound?
Correct Answer
D. Benzene
Explanation
Benzene is an aromatic compound because it contains a ring of six carbon atoms with alternating single and double bonds. This structure gives benzene its characteristic stability and resonance, making it highly reactive and aromatic in nature. Propanol, cyclohexane, and acetone are not aromatic compounds as they do not possess a conjugated ring system like benzene.
4.
There are a few homologous series of compounds. The existence of homologous series is due to:
Correct Answer
A. Functional groups
Explanation
The existence of homologous series is due to the presence of a functional group. Homologous series refers to a group of compounds that have similar chemical properties and a gradual increase in the number of carbon atoms in their structure. The functional group is responsible for determining the chemical behavior and properties of the compounds within the series. It provides a common characteristic that allows for the classification and comparison of these compounds. Cracking, isomerism, and polymerization are not directly related to the existence of homologous series.
5.
Which of the following compounds is heterocyclic?
Correct Answer
D. All of above
Explanation
Pyridine is a heterocyclic compound because it contains a ring structure with at least one heteroatom, in this case, a nitrogen atom. Heterocyclic compounds are organic compounds that have rings containing atoms other than carbon, such as nitrogen, oxygen, or sulfur. Pyrrole and thiophene are also heterocyclic compounds because they contain nitrogen and sulfur atoms, respectively, in their ring structures. Therefore, the correct answer is All of above .
6.
Select from the following one, which is an alcohol:
Correct Answer
A. CH3CH2OH
Explanation
The correct answer is CH3CH2OH. This compound is known as ethanol, which is a type of alcohol. It is formed by the combination of two carbon atoms, six hydrogen atoms, and one oxygen atom. Ethanol is commonly found in alcoholic beverages and is used as a solvent, fuel, and in the production of various chemicals.
7.
Lassaigne’s solution is prepared for the detection of nitrogen, sulfur, and halogens in organic compounds. Which metal is used for the reaction with the organic compound?
Correct Answer
B. Sodium
Explanation
Lassaigne’s solution is a reagent used for the detection of nitrogen, sulfur, and halogens in organic compounds. In this case, the metal used for the reaction with the organic compound is sodium. Sodium can react with certain organic compounds to form specific products or undergo specific reactions that help in the identification or detection of elements present in the compound.
8.
When AgNO3 is added to Lassaigne’s solution, which color change indicates the presence of r iodine?
Correct Answer
D. Deep yellow
Explanation
When silver nitrate (AgNO3) is added to Lassaigne's solution, which typically contains compounds like sodium, potassium, and sulfur, a deep yellow color can form due to the presence of iodine. This reaction occurs because silver ions (Ag+) react with any halide ions present in the solution, including iodide ions (I-).
9.
How many carbon atoms does the simplest molecule of a buckyball contain?
Correct Answer
C. 60
Explanation
The correct answer is 60 because a buckyball is a spherical fullerene molecule made entirely of carbon atoms. It consists of 60 carbon atoms arranged in a pattern of hexagons and pentagons, similar to a soccer ball. Therefore, the simplest molecule of buckyball contains 60 carbon atoms.
10.
If a molecule contains more than one functional group it is known as:
Correct Answer
B. Polyfunctional
Explanation
A molecule that contains more than one functional group is known as polyfunctional. This means that the molecule has multiple reactive sites, allowing it to undergo various chemical reactions and participate in multiple types of interactions. This term is used to describe compounds that have multiple functional groups, such as alcohols, amines, carboxylic acids, and others. These functional groups can greatly influence the properties and reactivity of the molecule, making it versatile in different chemical processes.