First Year Syllabus Test-1

Explanation: D

Explanation: D

Explanation: C
Angles 30° and 60° give the same range
30° + 60° =90°
Complementary Angles Give the Same Range.

Explanation: B

Explanation: C
For maximum KE X = 0, therefore KE max = 1/2 kXo².

Explanation A

Explanation: C
We have the following two states:
For state A: C_P – C_V = R, that is, the gas behaves as ideal gas.
For state B: C_P – C_V = 1.6R, (≠ R), this implies non-ideal behavior of gas.
Ideal gas behavior is typically observed at:
High temperature
Low pressure
Thus, we can say that P_A < P_B and T_A > T_B.

Explanation C

Explanation: D
Note: V-t graph is very important regarding entry test point of view
a(1): The tangent line is sloping upward from left to right ⇒ positive slope ⇒ positive acceleration
a(2): The tangent is flat (horizontal) ⇒ zero slope ⇒ zero acceleration
a(3): The tangent is sloping downward ⇒ negative slope ⇒ negative acceleration
a(1)>0 (positive)
a(2)=0
a(3)<0 (negative)

Explanation: B

Explanation: D

Explanation: D
The velocities are interchanged in case of head-on elastic collision of identical masses. Hence, option (D) is correct.

Explanation: A
When angular velocity is increasing:
Angular acceleration is in the same direction as angular velocity.
Angle between angular velocity and angular acceleration = 0°
When angular velocity is decreasing:
Angular acceleration is opposite to the direction of angular velocity.
Angle between angular velocity and angular acceleration = 180°

Explanation: D

Explanation: D
During isothermal change, T = constant ⇒ ΔU = 0.
Also, from the first law of thermodynamics, ΔQ = ΔW.

Explanation: D
Terminal velocity is reached when net force becomes zero:
Weight =Air drag (resistance)
This only happens in a fluid or gas, like air or CO₂, where resistance opposes motion.
Now in Vacuum, there will be no buoyant force or viscous drag force.
So the object falls freely under gravity, accelerating continuously until hit the ground or any other object. So, sphere never attains terminal velocity.

Explanation: C

Explanation: C

Explanation: B
PE = KE + Wfriction, 
mgh = KE + W,
10 × 10 × 10 = 900 + W,
W = 1000 – 900 = 100J.

Explanation: D
All of the mentioned quantities have same dimensions i.e. [T^–1].
Angular frequency (ω)
• Defined as: ω = 2πf
• Dimensions of frequency f = [T^–1]
• So, angular frequency also has dimensions = [T^–1]
A. Angular velocity (ω)
• Even though the name differs, angular velocity and angular frequency have identical units and dimensions:
→ [T^–1] (radians per second is dimensionless angle per time)
B. Decay constant (λ)
• From nuclear/radioactive decay law: N = N₀e^(–λt)
• To make the exponent dimensionless, λ must have units of 1/time, i.e.,
→ Dimensions: [T⁻¹]
 C. Frequency (f)
• Already established:
→ Dimensions: [T^–1]
D. All of these
• Since all three quantities have the same dimensions: [T^–1],
→ Correct answer is D.

Explanation: B

Explanation: D
In a cyclic process, a thermodynamic system undergoes a series of changes but returns to its initial state at the end of the cycle.
This means:
State functions (like temperature, pressure, volume, internal energy, enthalpy, entropy) all return to their initial values.
Path functions (like work and heat) do not necessarily return to zero because they depend on the path taken during the cycle, not just the start and end states.
A. Temperature
Temperature is a state function, so after a complete cycle, ΔT = 0.
B. Pressure
Pressure is also a state function, hence ΔP = 0 after a full cycle.
C. Enthalpy
Enthalpy is a state function, so ΔH = 0 in a cyclic process.
D. Work
Work is a path function, so ΔW ≠ 0 generally over a cyclic process.
In fact, the net work done by the system is equal to the net heat absorbed during the cycle (from the First Law of Thermodynamics).

Explanation: C

Explanation: A

Explanation: A

Explanation: B
On putting the bucket down, net force is directed upwards (otherwise the bucket would fall with acceleration = g) and displacement is downwards. Therefore, the angle between force and displacement is 180 degrees
W = Fdcos180 = mgh^–1 = –mgh.

Explanation: C
Angle between centripetal acceleration and linear velocity always remain 90 degrees.
The direction of angular acceleration and linear acceleration reverses when a body is slowing down.
other options
A. Angular velocity & Angular acceleration
Not always the same angle
If the object is speeding up, angular acceleration is in the same direction as angular velocity (angle = 0°).
If slowing down, angular acceleration is in the opposite direction (angle = 180°).
So, angle varies depending on the motion.
B. Linear velocity & Linear acceleration
Not always same angle
If accelerating in the same direction → angle = 0°
If decelerating → angle = 180°
If turning (e.g., in circular motion) → angle can be 90° or another value
So, angle changes based on motion.

Explanation: B
Complete vibration = 4x amplitude
Half vibration= 2x amplitude.

Explanation: A
It is given that
ΔQ = –20 J (Heat Release) ,
ΔW = –8 J (Wordk done on gas)
and U_i = 30 J.
From the first law of thermodynamics, we have
ΔQ = ΔU + ΔW
⇒ ΔU = (ΔQ – ΔW)
⇒ (U_f – U_i) = (ΔQ – ΔW)
⇒ (U_f – 30) = –20 – (–8)
⇒ (U_f – 30) = –20 +8
⇒ U_f = 18 J.

Explanation: C
Laplace corrected Newton’s formula for the speed of sound in gases by recognizing that sound waves cause rapid compressions and rarefactions, during which:
• No heat exchange occurs (i.e., the process is adiabatic, not isothermal).
• So, temperature changes within the wave (temperature increases during compression and decreases during rarefaction).
• However, the temperature of the surroundings remains unchanged, because the wave passes too quickly for thermal energy to be transferred to the surroundings. So:
Wave (localized region):
• Compression → temperature increases
• Rarefaction → temperature decreases
Surroundings (bulk medium):
• No net heat exchange
• Temperature remains same.

Explanation: D

Explanation: B
We know that
F_net = ma
When F_net = 0, then a = 0, that is, the velocity is constant.

Explanation: A
Just before striking all potential energy is changed to kinetic energy.
PE at start is = mgh = 5 × 2 × 10 = 100 J,
So KE just before striking would be 100J.

Explanation: D
Since the angular velocity is constant, there is no change in angular velocity with time. Angular acceleration is defined as the rate of change of angular velocity, so in this case, it is zero. Thus, the correct answer is D (None of these) because zero is not among the given options.

Explanation: B
Streamline flow (also called laminar flow) is a smooth, orderly flow of fluid in parallel layers, with no disruption between them.
High viscosity: Highly viscous liquids have more chances of streamlined flow because of greater force of attraction between the molecules.
Hints:
Low speed: Helps maintain streamline flow.
Low density: Less inertia, favors laminar flow.

Explanation A

Explanation: A
‘Smooth ER’ is involved in lipid synthesis and metabolism. 
‘Rough ER’ is involved in protein synthesis. 
The main job of ‘mitochondria’ is to perform cellular respiration. This means it takes in nutrients from the cell, breaks them down, and turns them into energy.
‘Vacuoles’, on the other hand, are organelles existing mainly to isolate potentially harmful waste materials. They do their task effectively by simply engulfing the waste material.

Explanation: A
RNA is synthesized through the process of transcription by using DNA as a template.

Explanation: A
Inhibitors, resemble with substrate molecules, join in the active site of the enzyme and inhibit the enzyme activity are called Competitive enzyme inhibitors.
Malonate is a competitive inhibitor of succinic dehydrogenase. The binding of succinic dehydrogenase to the substrate, succinate, is completely inhibited. Succinic dehydrogenase catalyzes the oxidation of succinate to fumarate in the Kreb’s cycle was an experiment demonstrated as an example of competitive inhibition.
So, the correct option is, ‘succinic dehydrogenase by malonic acid’

Explanation: C
The end products of glycolysis are two molecules of pyruvate, two molecules of ATP, and two molecules of NADH. The pyruvate produced in glycolysis is then transported into the mitochondria for further processing in the citric acid cycle if oxygen is available, or it undergoes fermentation in the absence of oxygen. 

Explanation: D
Dmitry lvanovsky is credited with discovering that the agent responsible for tobacco mosaic disease was filterable. His work laid the foundation for the discovery of viruses.

Explanation: A
In human gut carbohydrates are first digested in oral cavity.

Explanation: D
The human heart has four chambers:
Two upper chambers → Atria (Right atrium and Left atrium)
Thin-walled because they only receive blood and do not pump it with force.
Two lower chambers → Ventricles (Right ventricle and Left ventricle)
Thick-walled, especially the left ventricle, because they pump blood to lungs (right ventricle) and the entire body (left ventricle), which requires more force and pressure.

Explanation: A
A foreign substance, often a protein which stimulates the formation of immunoglobulins is called antigen.

Explanation: A
lysosomes are formed through the Golgi complex, depending on the type of cell and its function.

Explanation: C
Quantitatively rRNA is the major form of RNA in cell.

Explanation: B
Upon increasing the temperature, the shape of an enzyme’s active site may change. Enzymes have an optimal temperature at which they function most effectively. If the temperature becomes too high, the enzyme may undergo denaturation, where it loses its native structure irreversibly. Denaturation leads to a loss of enzyme activity as the active site is no longer able to bind with the substrate.

Explanation: C
In the Krebs cycle, also known as the citric acid cycle, the formation of succinate involves a series of chemical reactions, and substrate-level phosphorylation does not take place during the conversion of succinyl-CoA to succinate. The specific step where substrate-level phosphorylation occurs in the Krebs cycle is during the conversion of succinyl-CoA to succinate. In this step, the enzyme succinyl-CoA synthetase is involved, and it catalyzes the transfer of a phosphate group from succinyl-CoA to ADP, producing ATP and succinate. The overall reaction is as follows:
Succinyl-CoA + ADP + Pi (inorganic phosphate) → Succinate + ATP. 

Explanation: B
Viruses cannot be grown on artificial media because they are obligate parasites. This means they require a host cell to replicate and cannot reproduce independently outside of a living host organism

Explanation: D
Nearly all absorption of the products of digestion takes place in the ileum.

Explanation: A

Explanation: D

Explanation: C
Nucleolus is the darkly stained area within the nucleus and without any membranous boundary to separate it from the rest of the nuclear material. These are said to be the factory of ribosomes while ribosomes are said to be the factory of protein synthesis.

Explanation: C
Nucleotide consists of pentose sugar, nitrogenous base and phosphoric acid

Explanation: A
Pepsin is a protease enzyme, released in the stomach, alongside HCI. Because of HCI, the pH drops to significantly low levels however, this enzyme has adapted to work at maximum efficiency at a pH as low as 2.

Explanation: C
Glycolysis, the first stage of cellular respiration, occurs in the cytoplasm of the cell. It is a series of biochemical reactions that break down one molecule of glucose into two molecules of pyruvate. Unlike the subsequent stages of cellular respiration (such as the citric acid cycle and oxidative phosphorylation), glycolysis does not take place in the mitochondria. Instead, it occurs in the cytoplasm, which is the gel-like substance that fills the cell and surrounds the cellular organelles.

Explanation: A
The function of the viral capsid is A) To protect the viral genome. The viral capsid is the protein shell that surrounds the viral genetic material, whether it is DNA or RNA. It provides structural integrity and protection to the viral genome from the external environment, including physical and enzymatic degradation. The capsid helps to maintain the stability of the viral genome and ensures its successful delivery to host cells during infection.

Explanation: C
Protein components of food are digested by the enzymatic secretion of zymogen cells.

Explanation: C
One contraction and one relaxation constitutes a cardiac cycle.

Explanation: C
Each antibody consists of four polypeptides – two heavy chains and two light chains joined to form a “Y” shaped molecule.

Explanation: D
Unlike most other eukaryotic cells, mature red blood cells don’t have nuclei. When they enter the bloodstream for the first time, they eject their nuclei and organelles so, they can carry more hemoglobin, and thus, more oxygen. Each red blood cell has a lifespan of around 100–120 days.

Explanation: C
These are larger nitrogenous bases.

Explanation: A
Poisons like cyanide are irreversible inhibitors as they destroy the structure of the active sites of the enzymes by forming covalent bonds or physically blocking them. The rest are all reversible inhibitors, which do not damage the active site permanently and their effect can be reversed.

Explanation: D
When a molecule undergoes reduction, it gains electrons, hydrogen/protons, and often energy. The process of reduction is fundamental in many biological processes, including cellular respiration, photosynthesis, and various metabolic pathways. Redox reactions play a central role in transferring energy and driving chemical reactions in living organisms. In summary, option d) “all of the above” is the correct answer because reduction involves the gain of electrons and hydrogen/protons, and often results in the acquisition of energy by the molecule undergoing the reduction reaction.

Explanation: D
The characteristic of a retrovirus is D) The virus integrates its genome into the host cell genome. Retroviruses are a unique group of RNA viruses that undergo a reverse transcription process. They contain an RNA genome that is reverse transcribed by the enzyme reverse transcriptase into DNA. This DNA is then integrated into the host cell’s genome, becoming a permanent part of the host cell’s genetic material. Retroviruses, such as HIV, are known for their ability to establish a persistent and lifelong infection in the host due to this integration process

Explanation: A

Explanation: D
The backflow of blood from pulmonary artery is prevented by semilunar valve.

Explanation: B
The cell-mediated immune system consists of T-cells which originate in the bone marrow, but moves to the thymus where their development is completed. T-cells are highly-specialized cells in the blood and lymph. They fight bacteria, viruses, fungi, protozoans, cancer, etc. within host cells and react against foreign matter such as organ transplants.

Explanation: B
The ‘Golgi apparatus’ is a cellular organelle responsible for the modification and trafficking of proteins to other organelles such as the lysosome, the digestive organelle of the cell.

Explanation: A
Scale model of DNA was built by James D. Watson and Francis Crick, along with the assistance of Maurice Wilkins and Rosalind Franklin’s X-ray diffraction data, built the first accurate model of the structure of DNA. In 1953, they proposed the double helix model of DNA, which provided a clear understanding of the molecular structure and organization of DNA. Therefore, option A is correct.

Explanation: B
Enzymes require cofactors which are involved in the formation of enzyme-substrate complex and formation of product. If cofactor permanently attached by covalent bonds, it is called prosthetic group. If its detachabale, then it is called coenzyme.

Explanation: D
The end products of the electron transport chain are water and ATP. A number of intermediate compounds of the citric acid cycle can be diverted into the anabolism of other biochemical molecules, such as nonessential amino acids, sugars, and lipids.

Explanation: B
Viruses rely on the host cell’s machinery for reproduction. This includes using the host’s metabolism to generate energy and synthesize new viral components. Without a host, viruses can’t replicate, so their success hinges on the availability of a suitable host cell. The ability to hijack the host’s resources is key to their survival.

Explanation: C
The lymph vessel of villi is called lacteal.

Explanation: A
The arteries divide into smaller vessels called arterioles

Explanation: C
T cells mature in the thymus, while B cells mature in the bone marrow. Therefore, the statement that both T cells and B cells pass through the thymus is incorrect.

Explanation: A
The spindle fibre attaches to the centromere at a proteinaceous structure called the kinetochore.

Explanation: D
Water has a unique property, as it expands when temperature falls below 4°C (39°F). Water is most heavy at 4°C, therefore ice (solid water) is less dense than liquid water and this is the reason that ice floats in liquid water. Water body freezes on the surface at low temperature. Water has a high surface tension. In living cells this feature of surface tension allows a thin film of water to cover membranes and to keep them moist.

Explanation: D
All of these options are correct: If the pH of a solution changes slightly, it can result in a change in the ionization of the active site of an enzyme, the ionization of the substrate, and the retardation or blockage of enzyme activity.

Explanation: C
From one pyruvate, 3 NADH are produced by oxidative decarboxylation during Krebs cycle.

Explanation: C
Acellular life refers to life forms that lack cellular structures, such as organelles, membranes, or cytoplasm. Examples include viruses, viroids, and prions. Unlike cellular organisms, these entities rely on host cells for replication and metabolic processes. Viruses, for instance, contain genetic material but can’t replicate without a host. They are not truly “alive” outside of a host, which sets them apart from cellular life

Explanation: B
The jejunum is where most of the nutrient digestion and breakdown is finalized, preparing them for absorption.

Explanation: D
The heartbeat sound is made up of two distinct components:
• The “lub” (first sound) is caused by the closure of the atrioventricular (AV) valves (tricuspid and bicuspid/mitral) during ventricular contraction (systole).
• The “dub” (second sound) is caused by the closure of the semilunar valves (aortic and pulmonary) at the beginning of ventricular relaxation (diastole).

Explanation: D
Humoral immunity is mediated by B-lymphocytes (B cells), which produce antibodies to fight infections. T-lymphocytes, on the other hand, are involved in cell-mediated immunity. Options B and C are not valid types of lymphocytes.
Additional Information: What is Humoral Immunity?
“Humoral” refers to the bodily fluids or “humors.” In the context of immunology, humoral immunity involves the production of antibodies by B cells that are secreted into bodily fluids (such as blood and lymph) to neutralize pathogens. This aspect of the immune system is crucial for defending against infections and is a key component of our overall immune response.

Explanation: B
Bacteria is a prokaryote and lacks membrane-bound organelles, so they do not contain Golgi apparatus. All other mentioned structures are found in bacteria

Explanation: B
Therefore, the correct statement for the process in which large organic molecules are synthesized and a water molecule is removed is b) Condensation.

Explanation: C
The optimum temperature for the enzymes in the human body is 37˚C. When the temperature is increased from 30˚C, the rate of reaction is also increased. At 37˚C, the rate of reaction is maximum. If the temperature further increases, the rate of reaction decreases due to the denaturation of enzymes at high temperatures.

Explanation: D
Acetyl CoA is the link between glycolysis and Kreb’s cycle. Acetyl CoA is formed after decarboxylation of pyruvate. This acetyl CoA then enters Kreb’s cycle.

Explanation: A
The common cold is a viral disease. It is caused by Rhinoviruses. It causes fever and pain all over the body and affects the nose, throat, and air passages. AIDS (Acquired immunodeficiency syndrome)  is a disorder of the cell-mediated immune system of the body. It is caused by HIV (Human immunodeficiency virus). HIV is a retrovirus that attacks helper T cells.

Explanation: A
Alpha cells in the pancreas produce and secrete glucagon, a hormone that raises blood glucose levels. Beta cells, on the other hand, secrete insulin.

Explanation: C
ER is not involved in synthesis of conjugated molecules. Golgi apparatus does this.

Explanation: B
Option B is correct, as it is the correct molecular formula of lactose.

Explanation: B
Enzymes are the biological catalysts, which speed up rate of chemical reaction by lowering energy of activation.

Explanation: D
In the electron transport chain, electron carriers take electrons from NADH and FADH₂ and pass them through a chain of complexes. The ETC takes the energy from these electrons and pumps protons (H+) into the intermembrane space. This creates a gradient of a high proton concentration in the intermembrane space and a low concentration in the matrix of mitochondria. ATP synthase uses this energy to make ATP. One NADH makes 3 ATPs and one FADH₂ makes 2 ATPs.

Explanation: A
Viruses do not contain both DNA and RNA simultaneously. They can have either DNA or RNA as their genetic material, but not both at the same time. A virus is classified as either a DNA virus (contains DNA) or an RNA virus (contains RNA). For example, the influenza virus is an RNA virus, while the herpes simplex virus is a DNA virus. Some viruses have single-stranded genetic material (either DNA or RNA), while others have double-stranded genetic material. The presence of either DNA or RNA is one of the defining characteristics used to classify viruses into different groups.

Explanation: D
Parietal cells secrete HCl, which helps to activate digestive enzymes and maintain an acidic environment in the stomach, and intrinsic factor, a protein necessary for vitamin B12 absorption. Pepsinogen is secreted by chief cells.

Explanation: D
The number of mitochondria varies according to the activity of cells. 

Explanation: C
Phospholipid molecule has 2 fatty acids.

Explanation: C
Muscle cells perform lactic acid fermentation (a form of anaerobic respiration) during vigorous exercise.

Explanation: A
In HIV infected helper T-cells, the process of transcription occurs in nucleus while the process of reverse transcription occurs in cytoplasm.
The HIV virus undergoes a number of processes in the nucleus, cytoplasm, and viral capsid during its replication cycle.
In the nucleus:
Reverse transcription: The viral RNA is reverse transcribed into DNA by the reverse transcriptase enzyme.
Integration: The DNA is integrated into the DNA of the host cell by the integrase enzyme.
Transcription: The integrated DNA is transcribed into RNA by the host cell’s DNA polymerase.
In the cytoplasm:
Translation: The RNA is translated into proteins by the host cell’s ribosomes.
Protease cleavage: The proteins are cleaved by the protease enzyme into their active forms.
Assembly: The viral proteins and RNA assemble into new virions.
In the viral capsid:
Maturation: The virions are matured by the removal of the proteins that are not needed for infection.
Budding: The virions bud from the host cell membrane and are released into the extracellular environment.

Explanation: B
Hemoglobin breakdown produces bilirubin, which is processed by the liver and excreted in bile.

Explanation: C
The cytoplasm isn’t just empty space-it’s a bustling, dynamic region of the cell where numerous processes like metabolic pathways, protein synthesis, and storage of essential molecules occur. Think of the cytoplasm as a multitasking workspace, where enzymes, substrates, and various chemicals are always on the move, creating energy and building essential components. It’s busy, active, and absolutely vital for cell survival

Explanation: C
The linkage between the hydroxyl group of carboxyl group of one amino acid and the hydrogen of amino group of another amino acid release H₂0 and C – N link, to form a bond called peptide bond.

Explanation: A
Glycolysis is the cellular process that can take place both in the presence and absence of oxygen. Glycolysis is the initial stage of cellular respiration, and it occurs in the cytoplasm of the cell. This process involves the breakdown of one molecule of glucose into two molecules of pyruvate, along with the production of a small amount of adenosine triphosphate (ATP) and reduced electron carriers (such as NADH).

Explanation: B
HAART, also known as combination antiretroviral therapy (cART), is the standard treatment for HIV/AIDS, involving a combination of antiretroviral medications to suppress viral replication.

Explanation: C
Germ cells (sperms and ova) are meiotic products, thus contain haploid number of chromosomes, whereas rest of the body cells are mitotic products.
Gametocytes are precursor cells that undergo meiosis to form gametes (sperms or ova). Although they are still diploid, they are part of the germ cell lineage.
A primary spermatocyte or primary oocyte is a classic example of a gametocyte.

Explanation: B
The tertiary structure is the overall folding of the polypeptide chain, and it is determined by the interactions between the side chains of the amino acids. These interactions include ionic and disulfide bonds. The tertiary structure gives information about the folding of the protein. Whereas, the primary structure is the sequence of amino acids in the polypeptide chain. The secondary structure is the local folding patterns of the polypeptide chain, such as alpha helices and beta sheets. Lastly, the quaternary structure of a protein is the arrangement of multiple polypeptide chains in a single protein molecule. This is carried about by the hydrophobic interactions between the polypeptide chains.

Explanation: B
Citrate, the first compound formed in the Krebs cycle (also known as the citric acid cycle or tricarboxylic acid cycle), has six carbon atoms. Its chemical formula is often written as C₆H₈O₇, indicating six carbon atoms, eight hydrogen atoms, and seven oxygen atoms. The Krebs cycle is a series of chemical reactions that takes place in the mitochondria of cells, and citrate is a key intermediate in this cycle.

Explanation: B
The genetic material (nucleic acid) of a virus is what makes it infectious, as it allows the virus to replicate within a host cell.

Explanation: B
Mitochondria were first observed in muscle cells due to their high energy requirements and abundance of these organelles.

Explanation: D
Option D is correct as Acylglycerols and Phospholipids, both are made of lipid molecule, hence they consist of glycerol

Explanation: C
The p24 protein is a core protein of the HIV virus, that surrounds the genetic material.

Explanation: C
Plant cells have a rigid cell wall composed of cellulose, whereas animal cells do not have a cell wall.

Explanation: D
The human body uses L-amino acids to build proteins, and D-amino acids are not typically incorporated into proteins.

Explanation: B
Chromatin is made of DNA and proteins (mainly histones), found in the nucleus before chromosomes condense.

Explanation: D
Steroids and terpenoids are types of lipids that do not contain fatty acids. Steroids have a characteristic ring structure, while terpenoids are composed of isoprene units. Waxes, on the other hand, are esters of fatty acids with long-chain alcohols

Explanation: B
Each base pair is separated by 0.34 nanometers along the helix axis.

Explanation: C
Moles of CH₄ = 32g/16g = 2
Vol. of CH₄ = 2 ×22.4dm³ = 44.8dm³.
Moles of SO₂ = 16g / 64g = 0.25
Volume of SO₂ = 0.25 × 22.4dm³= 5.6dm³
Total vol = 44.8dm³ + 5.6dm³
= 50.4dm³.

Explanation: C
Conduction of electricity occurs when there is a free-moving charge (electrons or ions), so the answer is C. 

Explanation: C
There are 2 central atoms bonded to each other with a single bond → this is 1 sigma bond.
• Each central atom is bonded to 2 surrounding atoms (total 4 surrounding atoms).
• Each of these surrounding atoms is double bonded to the central atom → each double bond = 1 sigma + 1 pi bond.
Let’s count:
Bonds between central atoms:
• 1 single bond → 1 sigma bond
Bonds from central atoms to surrounding atoms:
• 4 double bonds → Each contributes 1 sigma + 1 pi
Total = 4 sigma + 4 pi
Total bonds:
• Sigma bonds = 1 (central–central) + 4 (one per double bond) = 5 sigma
• Pi bonds = 1 per double bond × 4 = 4 pi.

Explanation: B
This is the Statement of Hund’s rule only according to kpk textbooks

Explanation: B
Correct Option: B. Precipitation occurs
Given: Ionic Product > Ksp:
The solution contains more ions than it can hold at equilibrium.
This means the solution is supersaturated.
To restore equilibrium, the excess ions come out of solution as precipitate.
A. More salt dissolves:
This happens only when
Ionic Product < Ksp.
If the solution is unsaturated, more salt can dissolve to increase ion concentration.
C. Solution is saturated:
A saturated solution is when
Ionic Product = Ksp, meaning the solution holds the maximum possible ions in equilibrium.
D. No precipitation occurs:
This would be true if
Ionic Product ≤ Ksp.
If Ionic Product < Ksp → No precipitation; more salt can dissolve.
If Ionic Product = Ksp → No net change; system is at equilibrium.

Explanation: D
A reducing agent is a substance that loses electrons and gets oxidized itself, while reducing another substance.
To be a good reducing agent, a substance should:
Easily lose electrons (i.e., undergo oxidation readily)
Therefore, it should have a high oxidation potential

Explanation: D
1 mole of Ca = 40g
0.2 moles of Ca = 1/5 × 40g = 8g.

Explanation: B
Amorphous solids are referred to as “pseudo solids “or “supercooled liquids” because:
• Lack of long-range order: Unlike crystalline solids, amorphous solids do not have a regular, repeating arrangement of particles throughout the structure.
• No sharp melting point: They gradually soften over a range of temperatures, similar to liquids.
• Examples: Glass, plastic, pitch, and gels.

Explanation C
To determine which molecule has the highest dipole moment, we must consider both:
Electronegativity differences (how polar individual bonds are), and
Molecular geometry (whether the dipoles cancel or reinforce each other).
All other molecules are symmetrical (even if they have polar bonds), causing their dipoles to cancel (Dipole moment = 0D).
NH₃ is asymmetrical and has strong polar bonds, leading to a net dipole moment (Dipole moment > 0 D).
Thus, NH₃ has the highest dipole moment among the given molecules.

Explanation: C

Explanation: B
Qc = [B]²/[A]
Qc = 4²/1 = 16
So Qc > Kc, it means there are more products than reactants so reaction will move reverse to achieve equilibrium.

Explanation: C
The oxidation number (also called oxidation state) of an element in its free or elemental state is always zero (0).
This is because, in the free state, atoms are not combined with atoms of other elements — they are neutral, so they neither gain nor lose electrons.

Explanation: B
No. of moles = 3g / 12g = 0.25
No. of atoms = moles × Na = 0.25 × Na.

Explanation: C
This information is taken from textbook table. The triclinic crystal system is the least symmetric among the seven crystal systems. In triclinic structures:
• All three sides are unequal.
• All three angles are unequal and none is 90°.
• There is no axis of symmetry.
From the textbook crystallography table, the substances and their crystal systems are typically listed as:

Explanation: D
The molecular geometry of SO₃ (sulphur trioxide) is:
• Trigonal planar
• Central atom (S) forms three double bonds with three oxygen atoms
• No lone pairs on sulphur
• Bond angles = 120°
• Molecule is flat (planar)
Let’s compare it with the options:
A. NH₃ (Ammonia)
• Geometry: Trigonal pyramidal
• Has 1 lone pair on nitrogen
• Bond angle ≈ 107°
• Not planar
B. PF₃ (Phosphorus trifluoride)
• Geometry: Trigonal pyramidal
• Has a lone pair on phosphorus
• Bond angle < 109.5°
• Not planar
C. XeO₃ (Xenon trioxide)
• Geometry: Trigonal pyramidal
• Has a lone pair on xenon
Not planar
D. BF₃ (Boron trifluoride)
• Geometry: Trigonal planar
• No lone pairs on boron
• Bond angles = 120°
• Planar molecule — just like SO₃.