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The correct option is base.

Key Points

• The basic solution can turn red litmus to blue.
• Add a few drops of solution from each text tube on litmus paper.
• The distilled water is neutral in nature and thus on adding it to litmus paper there is no color change in litmus paper.
• With the addition of a few drops of acidic solution on blue litmus paper, the litmus paper turns blue to red.
• With the addition of a few drops of basic solution on red litmus paper, the litmus paper turns red to blue.

Additional Information

• Litmus paper is a type of paper that is able to change its color with the addition of acidic or basic solutions.
• It is a measure of acidity and can be used as a pH indicator.
• Purple litmus paper is neutral.
• The litmus paper can show the color transition within the pH range of 4.5 to 8.3 at 25 degree Celsius.

The correct answer is -vinegar.

Key Points

• Odour of acetic acid
• It primarily resembles vinegar.
• Acetic acid is a colourless liquid
• It has a sharp, pungent smell and sour taste.
• The concentration of acetic acid in vinegar can range from 4 to 8 per cent, with higher concentrations resulting in a stronger smell.
• The smell is so strong because of the volatile nature of acetic acid.

Additional Information

• Odour of Tomato
• The chemical responsible for the odour of tomato is methyl ketone or 2-nonanone
• It gives a sweet, fruity aroma.
• Tomato odour is essential in the food industry as it adds flavour to various dishes.
• It also helps in attracting pollinators.
• Odour of Kerosene
• The odour of kerosene is primarily due to aliphatic hydrocarbons such as naphthalene and alkylbenzenes.
• These chemicals are typically present in small concentrations.
• Kerosene has a pungent odour due to its small concentration.
• Kerosene odour is essential in ensuring that the fuel is not contaminated with other substances, which can affect its performance and safety.

The correct option is no H3O+ ions are present. Litmus changes color only in the presence of H3O+ ions.

Key Points

• Dry HCI gas does not change the color of dry litmus paper because no H3O+ ions are present.
• Litmus changes color only in the presence of H3O+ ions.
• Dry HCl is not able to dissociate to give Hydrogen ions.
• Acids like HCl is only able to dissociate only in an aqueous medium.
• HCl is not aqueous and not the litmus paper is wet.
• Thus, there is no color change in litmus paper.

Additional Information

• HCl is the chemical formula of hydrochloric acid or hydrogen chloride gas.
• It is also known as muriatic acid.
• It is a colorless gas at room temperature.
• It has a pungent odor.
• Hydrochloric acid is an aqueous solution of hydrogen chloride gas.
• It is a strong acid and corrosive in nature.

The correct option is the Option 5.

Key Points

• Water and cement initially form a cement paste that begins to react and harden (set).
• This paste binds the aggregate particles through the chemical process of hydration. In the hydration of cement, chemical changes occur slowly, eventually creating new crystalline products, heat evolution, and other measurable signs.
• Setting of cement is an example of permanent change which is irreversible, hence is not a physical change.

Additional Information

• Ripening of fruit is a chemical change.
• When the fruit gets ripped, the pigments present in the fruit skin get changed and this process cannot get reversed.
• The burning of coal is a chemical change.
• When the coal gets burnt, the carbon present in the coal gets converted into a carbon dioxide gas.
• The burning of coal is an irreversible process.

The correct option is none of the above.

Key Points

• Graphite and diamond are made up of carbon elements.
• They are allotrophs of carbon.
• Graphite and diamond are able to show similar chemical characteristics.
• Thus, they can show the same chemical changes.
• Graphite is present in sheets or layers of carbon atoms that are weakly bonded to each other.
• Diamond has a strong 3-dimensional arrangement of carbon atoms and is hard in nature.

Additional Information

• Graphite and diamond cannot have the same degree of hardness because of the different arrangements and bonding of carbon atoms.
• The graphite has weak bonding and is present in powder form.
• Diamond has a strong bonding and is hard solid, thus, they cannot form the same degree of hardness and crystal structure.
• Thus, they cannot have similar electrical conductivity.

The correct answer is -amount of water in cells.

Key Points

• Stomata opening and closure is a process that regulates gas exchange and water balance in plants.
• The process is controlled by two main cells called the guard cells.
• Guard cells are located around the stomatal pore and are responsible for opening and closing the pore.
• The water uptake controls the opening of the stomata by the guard cells
• It leads to turgor pressure and an increase in the size of the guard cells.
• This causes the stomata to open and allow the exchange of gases
• Gases such as carbon dioxide and oxygen are exchanged between the plant and the atmosphere.
• The stomata's closure results from water loss from the guard cells and a decrease in turgor pressure.
• This causes the guard cells to shrink, resulting in the stomata closing
• Nucleus position and protein composition do not have any major effect on the stomata closure and opening.

The correct answer is -red and blue.

Key Points

• Chlorophyll
• Chlorophyll is the pigment found abundantly in green plants.
• It absorbs most efficiently in the blue and red regions of the visible light spectrum.
• Sunlight contains a large spectrum of light from red to blue spectrum, including green light.
• Chlorophyll absorbs light in the
• blue region of the spectrum the most, with peaks around 450 and 650 nanometers
• The absorbed red light with a peak at 700 nanometers.
• The green region of the spectrum is reflected, giving chlorophyll its green color.
• Chlorophyll a and b are the most abundant types of chlorophyll.
• Other pigments found in plants, such as carotenoids and phycobilins, also absorb light in different regions of the spectrum
• If the plants have large amounts of carotenoids, they appear red as they reflect red light.

Option 2 is not a correct match.

Confusion Points

• Thick, hard stems with branching near the base are called ​shrubs.

Key Points

• Plants are the producers on earth.
• It varies in size from small herbs and shrubs to tall trees.
• Levaes flatter in wind and are the sites where photosynthesis takes place.
• Leaves consist of leaf base and lamina.
• Leaves attach to the stem by the petiole,
• It is a small stalk-like structure that helps in attachment to the stem.
• Creeper has a weak stem, and it cannot stand upright, and is present on the ground.
• Pumpkin and watermelon are examples.
• A tree is a thick, hard stem with branches high on the plant.
• Banyan and neem are examples.

Additional Information Below is the diagram depicting the petiole location.

The correct answer is transpiration.

Key Points

• Plants are immobile and do not move.
• Plants are characterized by vascular tissue that aids in the movement of water and sucrose.
• Plants absorb water from roots and carry it with the help of xylem tissue.
• Transpiration is the removal of water from parts of plants, such as leaves.
• The water reaches great heights in trees because of suction pull caused by transpiration.
• It occurs via the stomatal opening.
• It helps in the maintenance of water inside the plant body.

Additional InformationEvaporation:

• It is a process in which liquid converts to vapor.
• It helps in maintaining the water cycle.
• Liquid water is converted to vapor from stagnant water, seas, and oceans.

Absorption:

• It is a process by which food substances are absorbed by cells of the intestine.
• It is a crucial step of digestion.

The correct answer is the Presence of both DNA and RNA.

Key Points

• Chloroplast is a green color plastid present inside a plant cell.
• Chloroplast is a double membrane structure.
• It is semiautonomous, and it has its DNA.
• DNA can replicates and forms its copy.
• Replication is a process in which DNA forms its copy with the help of a DNA template and the enzyme DNA polymerase.
• Chloroplasts contain their own DNA, which is separate from the nuclear DNA found in the cell's nucleus. While the presence of DNA is an important factor in chloroplast replication, it is not sufficient for self-replication.
• Both DNA and RNA play important roles in the self-replication of chloroplasts, which are organelles found in plant cells that are responsible for photosynthesis.​ 
• Chloroplasts contain their own DNA, which encodes for some but not all of the proteins required for their replication and functioning.
• In order for the proteins to be produced, the DNA must first be transcribed into RNA, which serves as a template for protein synthesis.
• DNA provides the genetic information required for chloroplast replication, while RNA molecules are involved in the transcription of genetic information into proteins. Both DNA and RNA are essential for the self-replication of chloroplasts.

Additional Information

• RNA :
• It is ribonucleic acid.
• It is the genetic material of bacteria, viruses, and viroids.
• It is less stable than DNA.