Test-2 (Full Syllabus Test)

Explanation: B
R ∝ sin(2θ)
So, to maximize the range, you want to maximize sin(2θ).
Shortcut – Key Rule to Remember:
sin(2θ) is maximum when 2θ = 90⁰
⇒ So, θ=45⁰ gives maximum range
Angles close to 45° will give larger range
than those further away from 45°

Explanation:  B
X_L = ωL (Inductive reactance)
X_C = 1/ωC (Capacitive reactance)
• When X_L > X_C → Inductive dominance
⇒ Current Lags Voltage
• X_C > X_L → Capacitive reactance
⇒ Current Leads Voltage.

Explanation A

Explanation D
The visible spectrum of light extends roughly from violet (≈ 400 nm) to red (≈ 700 nm) in wavelength.
Waves beyond the red end have longer wavelengths and lower frequencies than visible light.
These are known as infrared (IR) waves.
Electromagnetic Spectrum Order (increasing wavelength):
Gamma rays < X – rays < UV < Visible light < Infrared < Microwaves < Radio waves
Hints:
Beyond violet (shorter wavelength) → Ultraviolet
Beyond red (longer wavelength) → Infrared.

Explanation C
Both spheres are identical in shape, size, and mass.
They fall through different fluids:
Sphere A → viscous fluid (thicker, more resistance)
Sphere B → less viscous fluid (thinner, less resistance)
So,
vt ∝ 1/η
→ Higher viscosity → lower terminal velocity
Reaching terminal velocity:
In a more viscous fluid, drag builds up quickly → object reaches terminal velocity faster.
In a less viscous fluid, drag builds up slowly → it takes longer to reach terminal velocity.

Explanation C
Vacuum is reference
Vacuum = baseline
K = ε / ε₀ → Vacuum has K = 1. All other media have K ≥ 1.

Explanation: C

Explanation: C

Explanation D

Explanation: C

Explanation C

Explanation B
The time constant
τ = RC tells us how quickly a capacitor charges or discharges.
Shortcut:
Larger R → current is smaller
Larger C → needs more charge
→ Both make charging slower.

Explanation: B
For an adiabatic process, there is no heat exchange between the system and surroundings:
Q = 0
From the first law of thermodynamics:
ΔU = Q – W
ΔU = 0 – 12 =−12J
The internal energy decreases by 10 J, because the gas uses its internal energy to do work during expansion.

Explanation: C

Explanation C
In this case, acceleration increases as fuel burns and mass decreases → variable acceleration.
Increasing thrust = increasing acceleration → not constant!
A: In vacuum, free fall has constant acceleration g ⇒ uniform.
B: “Speeding up steadily” implies constant acceleration ⇒ uniform.
D: On a smooth incline, a = gsinθ is constant ⇒ uniform.

Explanation B

Explanation: B

Explanation: A

Explanation C
Increases due to gravity
After the highest point, gravity accelerates the projectile downward. The vertical component of velocity grows in magnitude (downward) while the horizontal component stays constant (ignoring air resistance), so the overall speed increases

Explanation A
Hint: More heat → more collisions
Shortcut: T↑ = R↑ (in metals)
For a metallic conductor that obeys Ohm’s law, the resistance (R) depends on temperature as:
R=R0(1 + αΔT)
B. Decreases: True for semiconductors, not metals.
C. Stays the same: Only for ideal conductors (not real metals).
D. Becomes zero: Only for superconductors at very low temperatures.

Explanation: C

Explanation B
Hint: Forward = help carriers
Shortcut: Forward bias fights the barrier
External voltage in forward bias reduces the built-in electric field, making it easier for carriers to cross.

Explanation A
Since no external force is mentioned and the balls move along a straight line:
Total momentum before collision = Total momentum after collision
Given:
• Mass of ball 1: m₁=2 kg, velocity before collision: u₁ = 8 m/s
• Mass of ball 2: m₂ = 4 kg, velocity before collision: u₂ = 2 m/s
• After collision, both balls move together at velocity v
: Apply Conservation of Momentum:
m₁ u₁ + m₂ u₂ = (m₁ + m₂ )v
Substitute values:
2 ⋅ 8 + 4 ⋅ 2 = (2 + 4) v
16 + 8 = 6v
24 = 6v ⇒ v = 24/6 = 4 m/s.

Explanation A
Threshold wavelength for tungsten = 2300 Å
Incident wavelength = , which is smaller than the threshold wavelength.
Since f ∝ 1/λ, the frequency for 1800 Å is greater than the threshold frequency, hence the photoelectric effect takes place.

Explanation A

Explanation B

Ripple in electronics, which refers to the AC component remaining in a DC power supply, is a disadvantage. A perfectly smooth DC voltage is the ideal for electronic devices, but rectifiers can only produce pulsating DC. The ripple is the undesirable leftover AC voltage or current that can negatively impact performance and cause damage over time. And full-wave rectifiers actually have a higher ripple frequency (twice that of half-wave), not lower.

Explanation: D

Explanation D
Momentum of a photon: p = h/λ.
Given λ = 0.01 Å = 0.01 × 10^–10 m = 10^–12 m.
So p = h/10^–12 = 10¹² h.

Explanation C
Use Continuity:
A¹v¹ = A²v² (A ∝ r²)
(4)² ⋅ 2 = (2²) ⋅ v₂ ⇒ 32 = 4v₂ ⇒ v₂ = 8.

Explanation B

Explanation C

Explanation: D
When a unit positive charge moves perpendicular to a magnetic field with unit velocity, the magnetic force acting on it is given by:
F = Bqv sinθ
For given condition:
q = 1, v = 1, sinθ = 1
So,
F = B.
This physical quantity B is called magnetic induction or magnetic flux density (also known as magnetic field strength).v

Explanation B
v = ωr
decreasing r ⇒ decreases v
ω = constant
Radius r is halved
Substitute:
v’ = ω ⋅ r/2 = 1/2 ωr = v/2.

Explanation: A
The coil is oscillating freely (moving back and forth).
When the magnetic dipole is brought near it:
Changing flux through the coil → induced currents → magnetic damping.
This opposing effect resists motion (just like friction), converting mechanical energy into heat.
This is a direct application of Lenz’s law and conservation of energy.
Shortcut Trick:
Whenever you see motion + conductor + magnetic field →
Think “Eddy currents oppose motion” → object slows down.

Explanation: B
720° = 2 × 360°= 2 × 2π = 4π radians.

Explanation: C
Φ₁ = BAcos0° = BA, Φ₂ = BAcos90° = 0
Ratio = 1 : 0­
Perpendicular surface → full flux; parallel → no flux.

Explanation: D
In a mammalian cell, proteins constitute about 18% of the total cell mass.

Explanation: C
The nucleolus, located inside the nucleus, is the site of ribosomal RNA (rRNA) synthesis and ribosome assembly.

Explanation: C
tRNA transports specific amino acids to the ribosome for protein assembly.

Explanation: B
When an enzyme-catalyzed reaction reaches a point where all active sites of the enzyme molecules are occupied, adding more substrate does not increase the reaction rate. This condition is known as enzyme saturation.

Explanation: D
In glycolysis, the energy investment phase uses ATP to activate glucose before energy is produced.

Explanation: A
Viruses always have a genome (DNA or RNA) enclosed in a protein coat. But they lack cellular machinery and enzymes for metabolism, don’t show response to stimuli on their own, and outside a host they’re inert—so among the options, only “contain genome” fits.

Explanation: A
The SA node, the heart’s natural pacemaker, is located in the upper right atrium.

Explanation: A
Swallowing occurs in three stages:
Oral stage – This is the voluntary phase where food is chewed and pushed by the tongue into the oropharynx.
Pharyngeal stage – Involuntary; involves reflex actions that move the bolus through the pharynx.
Oesophageal stage – Involuntary; the bolus is moved down the esophagus toward the stomach via peristalsis.

Explanation: C
KP textbook (For your information)
FAD is a coenzyme composed of riboflavin (vitamin B₂) linked to adenine dinucleotide. The flavin part of FAD comes directly from riboflavin.

Explanation: C
Vaccines contain antigens, which are weakened or inactive forms of pathogens (or their parts). These stimulate the immune system to produce antibodies without causing the actual disease.
Antibiotics → kill or inhibit bacteria, not stimulate immunity.
Hormones → regulate body functions, not immune response.
Enzymes → speed up chemical reactions, not related to antibody production.

Explanation: B
In the neck and superior mediastinum, the trachea is anterior (ventral) to the oesophagus, which lies posterior (dorsal).

Explanation: D
It takes place at the renal corpuscle, which is made up of two main parts:
Glomerulus – A network of tiny capillaries that receives blood from the afferent arteriole.
Bowman’s capsule – A cup-like sac that surrounds the glomerulus and collects the filtered fluid (called filtrate).

Explanation: D
During contraction, the I-band shortens as actin and myosin filaments slide over each other.

Explanation: D
Larger diameter, myelination, and shorter length can increase impulse velocity.

Explanation: D
Sperm are produced in the seminiferous tubules of the testes under the influence of hormones like FSH and testosterone.

Explanation: B
Incomplete dominance results in a blend of both alleles, leading to an intermediate phenotype, such as pink flowers from red and white parents.

Explanation: C
DNA/RNA probes are short, labeled nucleic acid sequences that are complementary to a specific DNA or RNA sequence of a pathogen or a mutation. When these probes hybridize (bind) with their target sequences, they help detect the presence of:

Explanation: B
Lamarck suggested that traits change based on use, and these changes are inherited.

Explanation: A
Somatic cells (body cells) in humans are diploid (2n), meaning they have 2 sets of chromosomes — a total of 46 chromosomes (23 pairs).
Germ cells (sperm and egg) are haploid (n) — they have only 1 set of chromosomes, totaling 23 chromosomes.

Explanation: A
Chitin is a nitrogen-containing polysaccharide made of modified glucose molecules.

Explanation: C
NAD⁺ (Nicotinamide Adenine Dinucleotide) is a coenzyme that functions in oxidation–reduction (redox) reactions.
It contains a vitamin-derived part — nicotinamide, which comes from vitamin B₃ (niacin).
Structurally, it is made up of two nucleotides joined through their phosphate groups — one containing adenine and the other nicotinamide.
Hence, NAD⁺ includes both a vitamin-derived component and a nucleotide structure.

Explanation: D
Two turns yield 2 GTP, 6 NADH, and 2 FADH₂. None of the options exactly match.

Explanation: A
HIV (Human Immunodeficiency Virus) primarily attacks the CD₄⁺ T cells, also known as helper T cells.

Explanation: B
Intrinsic factor is a glycoprotein secreted by the parietal cells in the stomach lining. Its main function is to bind with vitamin B₁₂ and facilitate its absorption in the ileum of the small intestine.

Explanation: C
Lymph nodes are small, bean-shaped structures in the lymphatic system that filter lymph (a fluid containing white blood cells) and trap pathogens, such as bacteria and viruses. They also contain lymphocytes that help fight infections.

Explanation: C
Lung capacity varies with sex, height, and fitness, but a commonly cited textbook average is ≈5 liters for adults.

Explanation: C
Kidneys help maintain blood pH by excreting hydrogen ions and reabsorbing bicarbonate.

Explanation: A
A-band stays the same; it’s the region with thick filaments. Other bands and zones adjust during contraction.

Explanation: B
Repolarization is the return of the membrane potential to its resting state after depolarization, mainly through potassium ion outflow. During repolarization, K⁺ ions move out of the neuron through voltage-gated K⁺ channels, making the inside negative again and bringing it back toward the resting level. (Na⁺ channels are inactivated; sometimes it briefly goes below rest = hyperpolarization).

Explanation: D
LH stimulates Leydig cells in the testes to produce testosterone, crucial for male reproductive development.

Explanation: C
According to this law, alleles for a trait separate during the formation of gametes (meiosis), so each gamete gets only one allele

Explanation: B
Recombinant DNA technology involves inserting a gene that encodes a specific antigen  into another organism. This organism then produces the antigen, which is purified and used in the vaccine.

Explanation: B
According to Darwin’s theory of natural selection, variations that improve an organism’s chances of survival and reproduction are called useful (or favorable) variations. These variations help organisms adapt better to their environment and are passed on to future generations.
A. Harmful variations → decrease survival chances.
C. Artificial variations → result from human-controlled breeding (artificial selection).
D. Inherited mutations → are changes in DNA, but not all mutations are beneficial.

Explanation: C
The nucleolus is responsible for synthesizing and assembling ribosomal RNA (rRNA).

Explanation: C
Phospholipids have both water-attracting and water-repelling parts, making them ideal for forming cell membranes.

Explanation: A
A cofactor—either a metal ion or an organic coenzyme—binds to an apoenzyme, inducing the proper conformation of the active site and forming the holoenzyme. “Proteins” (option C) is too vague; most enzymes are already proteins and do not become active merely by adding generic protein.

Explanation: B
Viruses lack cellular metabolism—so they do not excrete waste. They can crystallize (used in early structural studies), infect bacteria (bacteriophages), and mutate readily, especially RNA viruses.

Explanation: B
The spleen filters blood, stores white blood cells, and is the largest lymphoid organ.

Explanation: A
Insulin (from pancreatic β-cells) lowers blood glucose by increasing glucose uptake in muscles and fat and promoting glycogen formation in the liver. Glucagon does the opposite (raises glucose), estrogen is a sex hormone, and ADH controls water balance.

Explanation: B
Neutrophils are the most numerous type of WBC and are the first responders during infection.
“This is from non-specific defence mechanism which is not included in syllabus but this is a general information that all students should know and it can come in MDCAT. If we look at the previous years KMU MDCAT, They had included these kind of general MCQS”.

Explanation: A
In tissues, CO₂ enters RBCs → forms H₂CO₃ → dissociates to H⁺ + HCO₃^–. HCO₃^– exits the RBC and enters plasma, and Cl^– moves inside RBC (chloride shift) to preserve charge balance. In the lungs, the reverse chloride shift occurs.

Explanation: C
At rest, the kidneys receive about 20–25% of cardiac output (~1.0–1.2 L/min from ~5 L/min CO). This high flow supports filtration rather than high metabolic demand.

Explanation: C
Smooth muscles are involuntary and are found in walls of internal organs like the stomach and intestines.

Explanation: D
A synapse is the small gap between two neurons where neurotransmitters are exchanged.

Explanation: B
Seminal prostaglandins stimulate uterine/oviduct contractions and thin cervical mucus, aiding sperm movement. Androgens/testosterone are systemic hormones, and oxytocin is a posterior pituitary hormone—not a semen component.

Explanation: B
Holandric traits are those carried on the Y chromosome and passed only from father to son.

Explanation: C
Smooth er makes lipids and helps remove harmful substances.

Explanation: D
Steroids and terpenoids do not contain fatty acid chains, unlike triglycerides or phospholipids.

Explanation: D
Pancreatic lipase functions best in a slightly alkaline environment (around pH 8).

Explanation: C
Cellular respiration is the process of breaking down glucose in the presence of oxygen to generate ATP, the energy currency of cells.

Explanation: C
HIV is a retrovirus with a positive-sense single-stranded RNA genome (two copies). Inside infected cells, reverse transcriptase makes cDNA from this RNA, but the virion itself carries RNA, not DNA.

Explanation: A
Pancreatic amylase is secreted in active form. In contrast, proteases are secreted as inactive precursors (trypsinogen, pepsinogen, chymotrypsinogen) to prevent autodigestion.

Explanation: A
Passive immunity = receiving pre-formed antibodies (natural: placenta IgG, breast-milk IgA; artificial: antibody injections). Prior infection and vaccines produce active immunity by stimulating the host’s own immune response.

Explanation: A
About ~7% of CO₂ is carried physically dissolved in plasma. Roughly ~23% binds to hemoglobin as carbamino compounds, and about ~70% is transported as bicarbonate (HCO₃^–).

Explanation: C
W Juxtamedullary nephrons have long loops of Henle that extend deep into the medulla and are accompanied by vasa recta, establishing the medullary osmotic gradient via the countercurrent multiplier/exchanger—key for urine concentration. Cortical/subcapsular nephrons have short loops and contribute less to concentration.

Explanation: C
Osteocytes are mature bone cells trapped in lacunae of the mineralized matrix and connect via canaliculi. Chondrocytes occupy lacunae in cartilage (not bone). Osteoblasts line bone surfaces and form new bone, while osteoclasts resorb bone and sit in Howship’s lacunae (resorption bays), not the matrix lacunae that house osteocytes.

Explanation: D
The ANS governs involuntary functions—cardiac modulation, smooth muscle tone, and glandular secretion. Conscious thought and emotions arise from cortical/limbic activity, not direct ANS control (though emotions can trigger ANS responses).

Explanation: C
Regression of the corpus luteum just before menses causes a sharp drop in progesterone and estrogen—their lowest point occurs at the onset of menstruation. This fall releases pituitary negative feedback, so FSH (and then LH) begin to rise in the early follicular phase.

Explanation: C
A monohybrid cross of Rr × rr produces 50% Rr (round) and 50% rr (wrinkled) — a 1:1 ratio.

Explanation: C
Chimpanzees have a total of 48 chromosomes, arranged in 24 pairs. Humans, by comparison, have 46 chromosomes (23 pairs).

Explanation: A
A triglyceride consists of three fatty acids attached to a single glycerol backbone.

Explanation: A
Cyanide binds irreversibly to the iron-containing active site of cytochrome oxidase in the mitochondrial electron transport chain. This prevents oxygen from accepting electrons, blocking cellular respiration. Because cyanide binds to a site other than the substrate’s active site (and alters enzyme function even when substrate is present), it acts as a non-competitive inhibitor, not a competitive one.

Explanation: D
KP textbook
1 Palmitic acid give eight acetyl grps and generate 129 atp molecules.

Explanation: A
The capsid is the protective protein coat of a virus, built from capsomere subunits. A phage is a bacteriophage (a virus that infects bacteria), a viroid is a small infectious RNA without a protein coat, and “DNA sheath” isn’t a standard term for viral structure.

Explanation: B
Arteries carry blood away from the heart and experience high pressure from heart contractions. To withstand this pressure, they have thicker, more muscular and elastic walls.

Explanation: D
Kidney stones may form due to excess excretion or high blood levels of certain substances.
• Hypercalcemia → leads to calcium stones (e.g., calcium oxalate).
• Hyperoxaluria → promotes oxalate crystal formation.
• Hyperuricemia → causes uric acid stones.
Thus, all listed conditions can contribute to kidney stone formation.

Explanation: C
Relaxation requires removal of cytosolic Ca²⁺. SERCA (Ca²⁺-ATPase) actively pumps Ca²⁺ into the SR, Ca²⁺ dissociates from troponin C, tropomyosin re-covers actin’s binding sites, and cross-bridges stop cycling. Na⁺/Ca²⁺ exchange is not the primary mechanism in skeletal muscle.

Explanation: C
When a neuron is excited, depolarization occurs as Na⁺ ions rush into the cell, causing the membrane potential to reverse from negative to positive. The peak (active) membrane potential during an action potential is about +50 mV, after which repolarization restores the resting potential.

Explanation: C
Penicillin (especially benzathine penicillin G) is the treatment of choice for all stages of syphilis—primary, secondary, latent, and tertiary. It is highly effective against Treponema pallidum, the causative bacterium. In patients allergic to penicillin, alternatives like doxycycline or azithromycin may be used, but penicillin remains the gold standard therapy.

Explanation: B
Linked genes tend to be inherited together and are found on the same chromosome.

Explanation: C
The Golgi complex consists of stacks of flattened membrane-bound sacs called dictyosomes (especially in plant cells). These are responsible for modifying, packaging, and transporting proteins and lipids within the cell. Each dictyosome is composed of several cisternae, which form the functional layers of the Golgi apparatus.

Explanation: A
Hair is rich in keratin, a fibrous (not globular) protein. Globular proteins are typically compact/spherical, made of polypeptide chains, and water-soluble (e.g., enzymes, hemoglobin, albumin).

Explanation: C
Cartilaginous joints (amphiarthroses) allow limited movement and are connected by cartilage.
• Intervertebral joints contain fibrocartilage discs (symphysis type).
• Wrist and ankle bones have limited movement due to cartilaginous connections.
In contrast, fibrous joints are immovable (e.g., skull sutures), and synovial joints are freely movable (e.g., shoulder, knee).

Explanation: D
The pons contains nuclei that help regulate the sleep–wake cycle, including the transition between wakefulness, sleep, and dreaming (REM sleep). It acts as a key relay between higher brain centers and the medulla, integrating neural signals for arousal and dreaming activity.

Explanation: A
Males have XY chromosomes, which are non-homologous and heteromorphic (differ in shape and genetic content).

Explanation: D
Water is polar, forms extensive hydrogen bonds, and acts as a near universal solvent. Unlike most liquids, water becomes less dense when it freezes because its hydrogen-bonded crystal lattice (ice) is more open, increasing volume and lowering density—hence ice floats.

Explanation: D
Multipolar neurons—having one axon and multiple dendrites—are the most common type in the central nervous system (CNS). They allow complex integration of information. Bipolar neurons occur in sensory organs (e.g., retina, olfactory epithelium), while pseudounipolar neurons are typical of sensory ganglia in the PNS.

Explanation: C
The uterus is a hollow, muscular organ situated in the pelvic cavity. It is pear-shaped (inverted)—broad at the upper end (fundus) and narrow at the lower end (cervix). Its structure and thick muscular walls make it ideal for implantation and development of the embryo during pregnancy.

Explanation: B
Each child has a 50% chance of inheriting the mutant X gene from the carrier mother.

Explanation: B
Pyrimidines (cytosine, thymine, uracil) have a single-ring structure. Purines (adenine, guanine) are double-ringed. Options C and D refer to chemical bonds, not ring count.

Explanation: B
In prophase I, crossing over occurs between non-sister chromatids of homologous chromosomes, creating recombinant chromatids. This reshuffles alleles and increases genetic diversity in gametes. Duplication occurs earlier (S phase), exchanging identical parts wouldn’t create new combinations, and exchanges between non-homologous chromosomes are aberrations, not normal meiosis.

Explanation: B
1 atom of sulphur = 32 amu
1 mole of sulphur = 32 amu × Na.

Explanation: C
Carboxylic acids (R–COOH) have a carboxyl group (–COOH) which consists of a carbonyl (C = O) and a hydroxyl (–OH) group attached to the same carbon.
The principal reactions of carboxylic acids occur at the carboxyl carbon, which is electrophilic in nature.
However, instead of direct addition (like aldehydes/ketones), the reactions proceed through a nucleophilic acyl substitution mechanism.

Explanation: B
Displacement reaction
Zn(s) + CuSO₄(aq) → ZnSO₄(aq) + Cu(s)
Zinc is more reactive → it oxidizes to Zn²⁺, while Cu²⁺ is reduced to Cu(s) that deposits on the Zn rod.
So Zn is oxidized (not reduced) and Cu²⁺ is reduced (not oxidized).
When a zinc rod is placed in a copper sulphate solution, a displacement reaction occurs where zinc displaces copper, causing the blue color of the solution to fade as copper sulphate is converted to colourless zinc sulphate. Solid copper metal is deposited onto the zinc rod, and the zinc itself dissolves into the solution, forming zinc ions.

Explanation: C
Ionization energy increases along the period & group 5 has greater IE than group 6.
Thus, Nitrogen (N) has the highest first ionization energy among the options due to its extra stability of half-filled p orbitals.

Explanation: C
Ceruloplasmin, synthesized in the liver, carries 65–90% of copper in blood plasma, essential for strong bone formation and melanin synthesis. Excess copper, however, can be toxic.

Explanation B

Explanation: D
The greater the number of withdrawing groups attached to acid, greater is its acidity.
–Cl groups are strong –I (electron-withdrawing) substituents. More Cl atoms pull electron density away from the –COO⁻ in the conjugate base, stabilizing it and increasing acidity. Thus acidity increases with the number of α-chlorines:
CCl₃COOH > CHCl₂COOH > CH₂ClCOOH > CH₃COOH.

Explanation: D
Oxidation states of I in options:
HI: I = −1
I₂: I = 0
HIO₃: I = +5
IF₇: I = +7 (maximum for iodine).

Explanation: C
In fruit juice production, the goal is to:
Break down plant cell walls (mainly composed of cellulose, hemicellulose, and pectin),
Increase juice yield, and
Clarify the juice by removing suspended particles.

Explanation: D
Trend: Reactivity with water increases down the group due to decreasing ionization energy.
Order: Li < Na < K < Rb < Cs
Tip: Always remember that heavier alkali metals (like Rb and Cs) are dangerously reactive with water.

Explanation: C
Reasoning (particles = molecules/atoms as appropriate):
• 2 g H₂ → 2/2 = 1.0 mol molecules → 1.0 N_A particles
• 20g Ca → 20/40 = 0.5 mol atoms → 0.5 N_A particles
• 34.5 g Na → 34.5/23 = 1.5 mol atoms → 1.5 N_A particles
• 120 gl₂ → 120/254 ≈ 0.47 mol molecules → ≈ 0.47N_A particles
Largest number of particles corresponds to the largest moles → Option C.

Explanation: A
• Beryllium oxide (BeO) is amphoteric, meaning it can react with both acids and bases:
BeO + 2HCl → BeCl₂ + H₂O
BeO + 2NaOH + H₂O → Na₂ [Be(OH)₄]
• Other group 2 oxides (MgO, CaO, SrO, BaO) are basic in nature and do not show amphoterism.
◈ Hence, BeO (from Beryllium) is the only amphoteric oxide in Group 2.

Explanation: C
Catalysis at a solid surface happens at active sites. Finely divided powder has the largest surface area per mass, exposing the most sites for adsorption of reactants → highest rate enhancement. Blocks or larger pieces have far fewer accessible sites.