RSMSSB Lab Assistant Paper 2 Mock Test - 4 Free Online Test 2026

The part ′B′ in the graph represents partial pressure of oxygen.

The Oxygen dissociation curve represents the relationship between the partial pressure of oxygen (usually on the X-axis) and the percentage of saturation of Hemoglobin (usually on the Y-axis).

Photophosphorylation is the conversion of ADP to ATP using the energy of sunlight by activation of PSII. This involves the splitting of the water molecule in oxygen and hydrogen protons (H⁺), a process known as photolysis.

Osteichthyes is a class of fish that includes bony fish. Some of the characteristics of this class include:

• Body is streamlined and mouth is terminal: This characteristic is correct and would not be excluded from the list of characteristics of Osteichthyes.

• Gills are covered by operculum: This characteristic is correct and would not be excluded from the list of characteristics of Osteichthyes.

• Skin covered with cycloid and placoid scales: This characteristic is incorrect and would be excluded from the list of characteristics of Osteichthyes. Osteichthyes have scales on their skin, but these scales are not necessarily cycloid or placoid.

• Many of them are viviparous: This characteristic is incorrect and would be excluded from the list of characteristics of Osteichthyes. Many Osteichthyes are oviparous, meaning they lay eggs, rather than being viviparous, meaning they give birth to live young.

Therefore, the correct answer is (iii) and (iv).

Answer: Option D
The ionic size increases with the addition of electrons and decreases with the removal of electrons. S²⁻ has the largest size due to the highest electron repulsion among the given species.

(iii) and (iv) will form ideal solutions hence do not form azeotropes. Azeotropes have same composition in liquid and vapour form when distilled.

To determine which binary mixtures will have the same composition in the liquid and vapor phases, we need to identify mixtures that form ideal solutions. In an ideal solution, the composition of the liquid phase and the vapor phase is the same at equilibrium.

Here’s a brief analysis of each mixture:

1. Ethanol + Chloroform:

   • This mixture does not behave ideally due to strong hydrogen bonding interactions between ethanol and chloroform, which can cause deviations from Raoult's Law.

2. Nitric Acid + Water:

   • Nitric acid and water form a non-ideal solution. Nitric acid forms strong hydrogen bonds with water, resulting in significant deviations from ideal behavior. Thus, the composition in the liquid and vapor phases will not be the same.

3. Benzene + Toluene:

   • Benzene and toluene form an ideal solution. The interactions between benzene and toluene are similar, and thus the composition of the liquid and vapor phases will be the same.

4. Ethyl Chloride + Ethyl Bromide:

   • Ethyl chloride and ethyl bromide also form an ideal solution. The interactions between these two similar substances lead to minimal deviations from ideal behavior.

Based on the above analyses, the mixtures that will have the same composition in the liquid and vapor phases are:

2. (iii) and (iv)

So the correct answer is:

2. (iii) and (iv)

- Schiff’s reagent test is used to detect aldehydes. Phenols do not contain the aldehyde functional group, so they do not respond to this test.
- FeCl₃ test is specific for phenols, producing a violet color.
- Br₂ water test results in the decolorization of bromine due to the formation of bromophenols.
- Litmus test detects acidity; phenols are weakly acidic and can turn blue litmus red.
- Therefore, phenols do not respond to the Schiff’s reagent test.

This reaction is a bromination in the presence of Br2​ and FeBr3 a typical electrophilic aromatic substitution.

Structure Analysis:

• The compound has an amide group (−CONH−) attached to a benzene ring. This group is an electron-donating group due to resonance, activating the ring, particularly at the ortho and para positions relative to the −CONH− group.

Expected Product:

• Bromination will most likely occur at the para position (due to steric hindrance at the ortho position).
• Thus, the correct major product should have a bromine atom at the para position to the −CONH− group.

NBS in CCI₄ brings about allylic brom ination by free radical mechanism:

Large holes in ‘Swiss cheese’ are due to production of CO₂ by Propionibacterium sharmanii (a bacterium).

- Statement i is correct because the respiratory rhythm centre is indeed located in the medulla region of the brain, which is responsible for the basic rhythm of breathing.

- Statement ii is incorrect; the pneumotaxic centre moderates the functions of the respiratory rhythm centre by reducing the duration of inspiration, not enhancing it.

- Statement iii is correct as the chemosensitive area near the rhythm centre responds to elevated levels of CO2 and hydrogen ions, leading to adjustments in the respiratory process.

- Statement iv is incorrect; the text states that the role of oxygen in regulating respiratory rhythm is quite insignificant.

Thus, the correct statements are i and iii, making Option A the right answer.