1.
Which of following describe the gaseous state of matter?
Correct Answer
D. D) A gas has neither definite shape nor volume.
Explanation
The correct answer is d) A gas has neither definite shape nor volume. This is because gases do not have a fixed shape or volume. They can expand to fill the container they are in and can be compressed or expanded easily. Unlike solids and liquids, which have definite shapes and volumes, gases are highly mobile and can move freely.
2.
One of the assumption s of the ideal gas law is that:
Correct Answer
A. A) Molecules have no attraction to one another.
Explanation
The assumption of the ideal gas law is that molecules have no attraction to one another. This assumption is made because the ideal gas law assumes that gas particles behave as point masses, meaning they occupy no volume and do not interact with each other. In reality, gas molecules do have attractive forces between them, but these forces are assumed to be negligible in the ideal gas law equation. This assumption allows for simpler calculations and predictions of gas behavior under certain conditions.
3.
The phenomenon in which a substance exists in more than one crystalline form is known as:
Correct Answer
A. A) PolymorpHism.
Explanation
Polymorphism refers to the phenomenon in which a substance can exist in more than one crystalline form. This means that the substance can have different crystal structures while maintaining the same chemical composition. Polymorphism is commonly observed in materials such as minerals and pharmaceutical compounds, and it can have significant effects on their physical and chemical properties.
4.
A vapor is:
Correct Answer
C. C) A gas that is normally a liquid.
Explanation
A vapor is a gas that is normally a liquid. When a substance is heated, its particles gain energy and move faster, eventually breaking free from the forces holding them together in a liquid state. At this point, the substance transitions into a gas and becomes a vapor. This process is known as vaporization. Therefore, the correct answer is c) A gas that is normally a liquid.
5.
Polymorphism refers to compound having:
Correct Answer
B. B) Different crystal structure
Explanation
Polymorphism refers to the ability of a compound to exist in different crystal structures. This means that the compound can have different arrangements of its constituent molecules or atoms in the solid state. Each crystal structure will have its own unique arrangement and packing of the molecules or atoms. Therefore, option b) "Different crystal structure" is the correct answer as it accurately describes the characteristic of polymorphism.
6.
The max temp at which the two phase region exists in a mixture of two partially miscible liquid is known as:
Correct Answer
A. A) Upper con-solute temp.
Explanation
The upper consolute temperature refers to the maximum temperature at which a two-phase region exists in a mixture of two partially miscible liquids. At temperatures above the upper consolute temperature, the liquids become completely miscible. This term is commonly used in the study of liquid-liquid phase separation and is an important parameter in understanding the behavior of mixtures.
7.
Amorphous form of a drug dissolves_______ than the crystalline form.
Correct Answer
B. B) Faster.
Explanation
The amorphous form of a drug dissolves faster than the crystalline form because it lacks a defined crystal structure. The lack of a crystal lattice allows the amorphous form to have higher solubility and faster dissolution rates, making it more readily available for absorption in the body.
8.
Which of the following are properties or examples of amorphous solids?
Correct Answer
D. D) All of the above.
Explanation
The correct answer is d) All of the above. This is because amorphous solids do not have a crystal structure, meaning their particles are arranged randomly. They also do not have a definite melting point, as they gradually soften and become more fluid as they are heated. Additionally, amorphous solids can have a glassy appearance, such as glass itself. Therefore, all the properties and examples listed in options a), b), and c) are correct for amorphous solids.
9.
Mesomorphic substances:
Correct Answer
A. A) Are in between solid and liquid
Explanation
Mesomorphic substances are materials that exhibit properties between those of a solid and a liquid. These substances have a unique molecular structure that allows them to have some degree of order like a solid, but also the ability to flow like a liquid. This state is often referred to as the mesophase. Mesomorphic substances can further be classified into different types, such as nematic and smectic, which describe the specific arrangement and behavior of the molecules within the mesophase. Therefore, the correct answer is a) Are in between solid and liquid.
10.
What kind of liquid crystal consists of parallel molecules in layers?
Correct Answer
C. C) Smectic
Explanation
Smectic liquid crystals consist of parallel molecules arranged in layers. In this type of liquid crystal, the molecules are ordered within the layers but have no long-range order between the layers. This arrangement allows for unique properties and behaviors, such as the ability to flow like a liquid while maintaining some degree of order. Cholesteric and nematic liquid crystals, on the other hand, have different molecular arrangements and do not consist of parallel molecules in layers. Therefore, the correct answer is c) Smectic.
11.
The change of state from a solid directly to a gas is known as:
Correct Answer
C. C) Sublimation
Explanation
Sublimation is the process in which a solid directly changes into a gas without going through the liquid phase. This occurs when the temperature and pressure are such that the solid particles have enough energy to overcome the attractive forces holding them together and transition into a gas phase. Examples of substances that undergo sublimation include dry ice (solid carbon dioxide) and mothballs (naphthalene). Therefore, sublimation is the correct term to describe the change of state from a solid directly to a gas.
12.
Which of the following characteristics are NOT shared by liquid and gases?
Correct Answer
B. B) Indefinite volume.
Explanation
The characteristic of indefinite volume is not shared by liquids and gases. Liquids have a definite volume, meaning they have a fixed amount of space they occupy. Gases, on the other hand, do not have a definite volume as they can expand or contract to fill the space available to them. The other characteristics listed, such as ability to diffuse, indefinite shape, and fluidity, are shared by both liquids and gases.
13.
The process of converting ice to water by application of heat proceed with:
Correct Answer
B. B) An increase in energy and an increase in entropy.
Explanation
When ice is converted to water by the application of heat, the process requires an increase in energy. This is because heat is being added to the system in order to break the hydrogen bonds between the water molecules and overcome the intermolecular forces holding the ice together. Additionally, the process also leads to an increase in entropy. Entropy is a measure of the disorder or randomness in a system, and when ice melts into water, the molecules are able to move more freely, resulting in an increase in disorder and entropy. Therefore, the correct answer is b) An increase in energy and an increase in entropy.
14.
The phase rule was first discovered by
Correct Answer
B. B) Gibbs
Explanation
The phase rule, also known as the Gibbs phase rule, was first discovered by Josiah Willard Gibbs. He was an American scientist who made significant contributions to the field of thermodynamics. Gibbs' phase rule is a fundamental principle in thermodynamics that relates the number of phases, components, and degrees of freedom in a system. It provides a mathematical framework for understanding the behavior of complex systems, particularly those involving multiple phases and chemical reactions. Gibbs' work laid the foundation for modern thermodynamics and has had a profound impact on the field of chemistry.
15.
A mixture of three gases O2, N2, CO2 is
Correct Answer
A. A) 1-pHase system
Explanation
A mixture of three gases O2, N2, CO2 is a 1-phase system because all three gases are uniformly distributed and mixed together at the molecular level. In a 1-phase system, there is only one set of physical and chemical properties throughout the entire system. In this case, the gases are not separated into distinct phases or regions, but rather exist as a homogeneous mixture.
16.
A saturated solution of sodium chloride is a
Correct Answer
B. B) Two pHase system
Explanation
A saturated solution of sodium chloride is a two-phase system because it consists of two distinct phases - the solid phase (sodium chloride crystals) and the liquid phase (water). In a saturated solution, the maximum amount of solute (sodium chloride) has dissolved in the solvent (water) at a given temperature, resulting in a dynamic equilibrium between the dissolved solute and the undissolved solute. Therefore, the system is considered to have two phases.
17.
At a triple point
Correct Answer
A. A) Both the temp & pressure are fixed
Explanation
At a triple point, both the temperature and pressure are fixed. The triple point is the unique combination of temperature and pressure at which all three phases of a substance (solid, liquid, and gas) can coexist in equilibrium. This means that at the triple point, the substance can exist as a solid, liquid, and gas simultaneously, and the temperature and pressure must be fixed at specific values for this to occur. Therefore, option a) is the correct answer.
18.
A system with zero degree of freedom is known as
Correct Answer
C. C) Invariant
Explanation
A system with zero degree of freedom means that it has no independent variables or components that can vary. In other words, the system is fixed and unchanging, regardless of any external factors. Therefore, it can be referred to as "invariant" since it remains constant and unaffected by any changes.
19.
The number of components in a solution of common salt is
Correct Answer
C. 2
Explanation
Common salt, also known as sodium chloride (NaCl), is a compound made up of two components: sodium (Na) and chloride (Cl). Therefore, the correct answer is 2, as there are two components in a solution of common salt.
20.
The temp at which a polymorphic substance changes from one form to another is called
Correct Answer
D. D) Transition temp
Explanation
The correct answer is d) Transition temp. The transition temperature refers to the temperature at which a polymorphic substance undergoes a change from one form to another. This change can include transformations such as melting, freezing, or phase transitions. It is an important characteristic of polymorphic substances as it determines their behavior and properties at different temperatures.