Chemistry MCQs
Topic Notes: Chemistry
MCQs and preparation resources for competitive exams, covering important concepts, past papers, and detailed explanations.
Plato
- Biography: Ancient Greek philosopher (427–347 BCE), student of Socrates and teacher of Aristotle, founder of the Academy in Athens.
- Important Ideas:
- Theory of Forms
- Philosopher-King
- Ideal State
101
Describe the appearance of copper sulfate crystals.
Answer:
Blue
Copper sulfate crystals are known for their distinctive vibrant blue color. This color arises from the presence of copper ions in the crystal structure.
102
What type of ion will not form a crystalline structure with oppositely charged ions?
Answer:
H+
H+ is a positively charged hydrogen ion, which is not expected to form a crystalline structure with oppositely charged ions. The other options, H-, Mg2+, and Ca2+, are all ions that are capable of forming crystalline structures with oppositely charged ions.
103
Rutherfords planet like structure was defective and unsatisfactory because_________________?
Answer:
all
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104
What happens to a borax aqueous solution when it is heated above 62°C?
Answer:
Na2B4O7.5H2O
Heating an aqueous solution of borax above 62°C results in the evaporation of water molecules. Among the given options, Na2B4O7.5H2O is the correct structure for heptahydrate form of sodium tetraborate, which is formed when the solution is heated. Removing water molecules leaves behind Na2B4O7·5H2O crystals.
105
What explains the difference in states of matter between CO2 and SiO2 at room temperature?
Answer:
CO2 exists as individual molecules, whereas SiO2 has a network covalent structure.
The states of matter of CO2 and SiO2 at room temperature differ due to their structural differences. CO2 is a molecular compound with weak intermolecular forces, while SiO2 has a rigid network covalent structure, making it solid at room temperature.
106
What is the molecular structure of ethyne?
Answer:
linear
Ethyne, also known as acetylene, has a straight-line molecular structure due to its triple bond between the two carbon atoms, resulting in a linear geometry. This structure is characterized by a bond angle of 180 degrees.
107
What causes water's density to decrease when it freezes at 0°C?
Answer:
Empty space present in the structure of ice
When water freezes, its molecules arrange in a unique hexagonal structure that contains empty spaces. This causes the density of the solid ice to be lower than that of liquid water.
108
Which ketone has a symmetrical molecular structure?
Answer:
acetone
Acetone is a symmetrical ketone because it has a methyl group on both sides of the carbonyl group, resulting in a mirror-image molecular structure.
109
What is sintered glass primarily used for?
Answer:
filtration
Sintered glass is a porous material created by fusing small glass particles together. Its porous structure makes it suitable for various applications. In this multiple-choice question, we are asked about the primary use of sintered glass. Among the given options, 'filtration' is the correct choice. Other options like absorption, adsorption, and sublimation can be related to sintered glass's capabilities, but filtration is its primary use, as it allows the separation of solids from liquids or gases by trapping the particles within its porous structure.
110
What is the most stable allotropic form of phosphorus?
Answer:
Black
Black phosphorus is the most stable allotropic form of phosphorus, which is obtained by heating white phosphorus in the absence of air. It has a layered structure and is more stable than other allotropic forms due to its strong covalent bonds.