NEET Unit Test - 3 Free Online Test 2026

In case of ideal gases the average velocity is always zero. Hence the average momentum is zero. 
Whereas average speed is non- zero so the kinetic energy is also non-zero,  as these two are scalar quantities.

As we know, f=v/2l
Now, it will act as one end and one end closed.
So, f₀=v/2l’=v/4½=v/2l=f

According to kinetic theory of gases there is no intermolecular force of attraction between the molecule of gases but its not true as gases liquifise, at high pressure molecular interaction starts due to which pressure on the walls decreases as molecule dragged back so pressure exerted by real gas is less than ideal gas, due to repulsive forces molecule behave as small spheres and hence volume decreases

P=P1​+P2​=+2−1=+1 dioptre, lens behaves as convergent
F=1​/P=1/1​=1m=100cm

Huygen's construction of wavefront does not apply to origin of spectra which is explained by quantum theory

None of the provided options exactly match these concentrations.

A disproportionation reaction is a type of redox reaction where a single substance undergoes both oxidation and reduction, forming two different products.
Let's analyze each option:
(a) 2 F_2(g) + 2 OH^-_(aq) → 2 F^-_(aq) + OF_2(g) + H₂O(l)

• This reaction involves fluorine (F₂), which is reduced to F^- and oxidized to OF₂. Therefore, fluorine undergoes both oxidation and reduction.
• This is a disproportionation reaction.

(b) Cl_2(g) + 2 OH^-_(aq) → ClO^-_(aq) + Cl^-(aq) + H₂O(l)

• In this reaction, chlorine (Cl₂) is reduced to Cl^- and oxidized to ClO^-.
• This is a disproportionation reaction.

(c) 2 NO_2(g) + 2 OH^-_(aq)→ NO₃^-_(aq) + NO₂^-_(aq) + H₂O(l)

• In this reaction, NO₂ undergoes both oxidation and reduction to form NO₃^- and NO₂^-.
• This is a disproportionation reaction.

(d) 2 H₂O_2(aq)→ 2 H₂O(l) + O_2(g)
In this reaction, hydrogen peroxide (H₂O₂) decomposes into water (H₂O) and oxygen (O₂). Here, hydrogen peroxide undergoes reduction to form H₂O and oxidation to form O₂, but since it does not involve two different products from a single reactant, it is not a disproportionation reaction. It's a simple decomposition reaction.
Conclusion:The reaction in (a) is the disproportionation reaction, so the correct answer is (d) 2 H₂O_2(aq) → 2 H₂O(l) + O_2(g).

Primary batteries cannot be recharged and reused.

Acid ⇋ Conjugate Base  +  H⁺
By this definition,
HNO2 ⇋ NO₂^- + H⁺
CH₃NH₃+ ⇋ CH₃NH₂ + H⁺
C₆H₅COOH ⇋ C₆H₅COO^- + H⁺
H₃O⁺ ⇋ H₂O + H⁺
We can see that the conjugate base of H₃O+ is H₂O. But it is given that OH^- is the C.B. So option d is incorrect.

Option A is correct.

log₁₀Kp = 8 - 6400/T.

Convert temperature: T = 527 °C = 527 + 273 = 800 K.

Substitute T = 800 K into the formula: log₁₀Kp = 8 - 6400/800 = 8 - 8 = 0.

Therefore Kp = 10⁰ = 1.

For an equilibrium that involves only pure solids and CO₂(g), the activities of solids are unity, so Kp = p_CO2 (with pressure in atm). Hence p_CO2 = 1 atm, matching option A.

Electrolysis of H₂SO₄
Cathode:-
2H⁺  +  2e^-  -  H₂    (Reduction)

Anode:-
4OH^-  -  2H₂O  +  O₂  + 4e^-  (Oxidation)

OH^- ions discharged at anode.

(i) Oxidation state of element in its free state is zero.

(ii) Sum of oxidation states of all atoms in compound is zero.

O.N of S in S₈=0;    O.N of S in S₂F₂=+1

O.N of S in H₂S=-2

but pOH+ pH = 14  or pOH = 14 – pH

14 – 9.25 – 0 = pK_b pK_b = 4.75

Answer: D. Immigration (I) is not generally equal to emigration (E).

• Births (B) and deaths (D) are the primary factors determining population density (N) under normal conditions; immigration and emigration become important only in special situations.

• When a habitat is newly colonised, immigration (I) can be more important than natality (B) because individuals arriving from outside increase the population.

• B and I both increase N (positive contributions), while D and E decrease N (negative contributions).

• I equals E only at a dynamic equilibrium or in a perfectly closed and stable population; this is not generally true for most real populations, so the statement I is generally equal to E is incorrect.

Therefore, option D is incorrect.

The primitive atmosphere of earth was reducing atmosphere with little or no oxygen but was rich in water vapour, carbon monoxide, carbon dioxide, nitrogen and hydrogen. Thus, oxygen was not present in primitive atmosphere. The high temperature, UV light and lightening provided energy for chemical reactions between hydrogen and free oxygen, nitrogen and carbon to form, ammonia, methane and cyanides. Owing to the high temperature of earth, water was present in form of superheated steam and ammonia, methane and cyanides were present in gaseous form. 

Therefore, the correct answer is option C.

Topic in NCERT: Origin of life

Line in NCERT: "oxygen combined with ammonia and methane to form water, co2 and others."

Predators help control prey populations, often preventing prey from reaching excessively high densities. This is a natural ecological balance.

Topic in NCERT: Predation and its Ecological Role

Line in NCERT: "Some predators help in controlling their prey populations."

A. The Evil Quartet - III. Causes of biodiversity losses:

• The "Evil Quartet" refers to four major causes of biodiversity loss: habitat destruction, overexploitation, invasive species, and co-extinctions.
• These factors collectively threaten the survival of various species and ecosystems globally.

B. Ex situ conservation - I. Cryopreservation:

• Ex situ conservation involves conserving biodiversity outside their natural habitats, such as in seed banks, botanical gardens, or through cryopreservation.
• Cryopreservation is a technique used for freezing and storing genetic material (like seeds or embryos) at very low temperatures for future use.

C. Lantana camara - II. Alien species invasion:

• Lantana camara is an invasive alien species that disrupts native ecosystems by competing with native flora and causing ecological imbalances.
• Alien species invasions are a major contributor to biodiversity loss and ecosystem degradation.
• The environmental damage caused and threat posed to our native species by invasive weed species like carrot grass (Parthenium), Lantana and water hyacinth (Eicchornia).

D. Dodo - IV. Extinction:

• The Dodo is an example of a species that has gone extinct due to human activities such as hunting and habitat destruction.
• Extinction is the complete loss of a species, often driven by factors like overexploitation, invasive species, and habitat destruction.

The various serai stages of lithosere (succession on bare rock) are as follows:
Lichens (Pioneer community) → Mosses → Annual grasses→ Perennial grasses → Shrubs → Trees (Climax community).

In his experiment, Stanley Miller synthesised the following:
- Virus: Not synthesised by Stanley Miller in his experiment.
- Protein: Not synthesised by Stanley Miller in his experiment.
- Amino acid: Stanley Miller successfully synthesised amino acids in his experiment. Amino acids are the building blocks of proteins and are essential for life.
- Cell: Stanley Miller did not synthesise cells in his experiment.
Therefore, the correct answer is option C: Amino acid. Stanley Miller's experiment demonstrated that the conditions present in the early Earth's atmosphere can lead to the formation of amino acids, which is an important step in the origin of life on Earth.

Topic in NCERT: Origin of life
Line in NCERT: "he observed the formation of amino acids."

Hormones are generally proteincomponents having amino acids as well as steroids. Hormones are generally not monosaccharide derivatives in nature

The correct answer is B: Immunology.

- The thymus is a crucial organ in the immune system of humans.
- It is primarily responsible for the maturation and differentiation of T-lymphocytes or T cells, which are essential for the immune response.
- T cells play a critical role in recognizing and attacking pathogens such as bacteria, viruses, and other harmful substances in the body.
- The thymus helps in training T cells to distinguish between self and non-self antigens, thus preventing autoimmune reactions.
- Overall, the thymus is vital for the development and regulation of the body's immune responses.