All questions of December Week 3 for NEET Exam

• This statement is incorrect. A decrease in the level of blood plasma proteins would actually result in a decrease in osmotic pressure, leading to less water being drawn from tissues into the blood. Instead, it would cause water to accumulate in the tissues, leading to edema.

• This statement is correct. Blood plasma proteins, especially albumin, play a crucial role in maintaining the osmotic pressure of the blood.

Understanding Entropy
Entropy is a fundamental concept in thermodynamics and statistical mechanics that quantifies the level of disorder or randomness in a system. Let's explore this in detail.
Definition of Entropy
- Measure of Disorder: Entropy can be understood as a measure of how spread out or dispersed the energy in a system is.
- Randomness: A higher entropy value indicates greater randomness and less predictability in the arrangement of particles in a system.
Importance of Entropy
- Second Law of Thermodynamics: This law states that in any energy transfer or transformation, the total entropy of a closed system will either increase or remain constant. This is a reflection of natural processes moving towards a state of maximum disorder.
- Spontaneous Processes: Entropy helps to explain why certain processes occur spontaneously. For example, ice melting in a warm room increases the entropy of the system, as the structured ice molecules become more disordered in liquid form.
Comparison with Other Options
- Energy: While energy is related to the ability to do work, it does not directly measure disorder.
- Enthalpy: This is a measure of total heat content in a system, not specifically disorder.
- Mass: Mass refers to the amount of matter in a system and does not provide information about the arrangement or randomness of that matter.
Conclusion
In summary, the correct answer is option 'D' – Entropy – because it specifically defines a measure of disorder or randomness within a system, making it essential for understanding the behavior of thermodynamic processes.

 Refrigerator follows the principle of clausius statement of second law of thermodynamics. It does not violate second law of thermodynamics because it takes energy to transfer heat from low temperature body to high temperature body. Electrical work is given to refrigerator to extract heat from low temperature body and to transfer it to higher temperature body. If any refrigerator is transferring heat from low temperature body to higher temperature body without any external energy then we can say that it violates second law of thermodynamics.But in actual it takes energy to do.

(i) CH3F:

The central atom in CH3F is carbon, which has the electron configuration 1s2 2s2 2p2. Carbon forms four covalent bonds in this molecule.

To determine the hybridization, we count the number of regions of electron density around the central atom. In this case, we have one single bond to each hydrogen atom, one single bond to the fluorine atom, and one lone pair on carbon. This gives us a total of four regions of electron density.

The hybridization of an atom with four regions of electron density is sp3. Therefore, the carbon atom in CH3F is sp3 hybridized.

The shape of the molecule can be determined by looking at the arrangement of the regions of electron density. In this case, the lone pair and the three bond pairs are arranged in a tetrahedral geometry. However, the presence of a lone pair causes a distortion in the shape.

The lone pair occupies more space than the bond pairs and exerts a stronger repulsion. As a result, the bond angle between the three hydrogen atoms and the fluorine atom is slightly less than 109.5 degrees.

Therefore, the shape of CH3F is trigonal pyramidal.

(ii) HC:

The central atom in HC is carbon, which has the electron configuration 1s2 2s2 2p2. Carbon forms one covalent bond in this molecule.

To determine the hybridization, we count the number of regions of electron density around the central atom. In this case, we have one single bond to the hydrogen atom. This gives us a total of one region of electron density.

The hybridization of an atom with one region of electron density is sp. Therefore, the carbon atom in HC is sp hybridized.

The shape of the molecule can be determined by looking at the arrangement of the regions of electron density. In this case, there is only one bond pair, so there is no specific shape associated with HC. However, the bond angle between the carbon and hydrogen atoms is approximately 180 degrees.

Therefore, the shape of HC is linear.

The Kelvin-Planck statement is a fundamental principle of thermodynamics that is applicable to all heat engines. It states that:

No process is possible whose sole result is absorption of heat from a reservoir and all the heat is converted to work.

This statement implies that it is impossible to construct a heat engine that can extract heat from a single thermal reservoir and convert it completely into work. In other words, it is impossible to have a 100% efficient heat engine.

Explanation:

To understand the Kelvin-Planck statement, we need to have a basic understanding of heat engines. A heat engine is a device that converts heat into work. It operates on the principle of the Carnot cycle, which involves four processes: isothermal expansion, adiabatic expansion, isothermal compression, and adiabatic compression. The efficiency of a heat engine is defined as the ratio of the work output to the heat input. According to the second law of thermodynamics, the efficiency of a heat engine cannot exceed the efficiency of a reversible heat engine operating between the same two reservoirs.

The Kelvin-Planck statement is based on the fact that any heat engine must reject some heat to a low-temperature reservoir in order to operate. This means that not all of the heat energy can be converted into useful work. The statement implies that there must always be some waste heat that cannot be utilized to produce work. This is because all natural processes tend to move towards a state of maximum entropy, and the conversion of heat into work is a process that results in a decrease in entropy. Therefore, it is impossible to have a heat engine that can convert all of the heat energy it absorbs into useful work.

Conclusion:

In conclusion, the Kelvin-Planck statement is a fundamental principle of thermodynamics that states that it is impossible to construct a heat engine that can extract heat from a single thermal reservoir and convert it completely into work. This statement is based on the second law of thermodynamics, which states that all natural processes tend to move towards a state of maximum entropy. The Kelvin-Planck statement has important implications for the design and operation of heat engines, and it sets a fundamental limit on the efficiency of such devices.

Understanding Hybridization in CH3 - CH = CH - CN
To determine the hybridization of each carbon in the compound CH3 - CH = CH - CN, we analyze the bonding and geometry around each carbon atom.
1. Carbon 1 (CH3)
- This carbon is bonded to three hydrogen atoms and one other carbon atom.
- The geometry is tetrahedral.
- Hybridization: sp3
2. Carbon 2 (CH)
- This carbon is bonded to one hydrogen atom, one carbon atom (C1), and one carbon atom (C3) through a double bond.
- The geometry is trigonal planar due to the double bond.
- Hybridization: sp2
3. Carbon 3 (CH)
- This carbon is bonded to one hydrogen atom and one carbon atom (C2) through a double bond, and a cyanide group (CN).
- The geometry is also trigonal planar.
- Hybridization: sp2
4. Carbon 4 (CN)
- The carbon in the cyanide group is triple-bonded to nitrogen (N) and is also connected to carbon (C3).
- The geometry is linear due to the triple bond.
- Hybridization: sp
Summary of Hybridization
- Carbon 1: sp3
- Carbon 2: sp2
- Carbon 3: sp2
- Carbon 4: sp
Conclusion
The correct hybridization scheme for the compound CH3 - CH = CH - CN is sp3, sp2, sp2, sp. Thus, the correct answer is option 'A'.