Assertion (A): Most carbon compounds are poor conductors of electricity. Reason (R): Most carbon compounds have low melting and boiling points due to weak intermolecular forces.
Which of the following statements is/are not false?
Which of the following statements about energy flow and food chains is/are correct?
The ozone layer, although harmful to organisms at ground level, is crucial for the survival of life on Earth. Based on your understanding of ozone formation and UV radiation, which of the following would be a potential long-term ecological impact of a significant reduction in ozone concentration in the stratosphere?
Match the following parts of the human eye with their corresponding functions:
Assertion: The twinkling of stars occurs because the planets are very far from Earth and their light is refracted in the atmosphere. Reason: The twinkling effect is due to the continuous atmospheric refraction of starlight, which causes fluctuations in brightness, but planets do not twinkle because they are closer to Earth and appear as extended sources of light.
In an experiment for the production of hydrochloric acid (HCl) gas, a guard tube containing calcium chloride is used. What is the primary function of the calcium chloride in the guard tube?
Why does dry HCl gas not change the color of dry litmus paper?
How is the concentration of hydronium ions (H₃O⁺) affected when a solution of an acid is diluted?
Consider the following statements about biodegradability and the persistence of materials in the environment: Enzymes are highly specific in their action, and they can only catalyze the breakdown of certain organic compounds, preventing the digestion of substances like coal or plastics. Biodegradable substances are efficiently decomposed by natural biological processes into harmless components, but the speed of this breakdown is influenced by factors such as temperature, moisture, and microbial activity. Non-biodegradable materials, like plastics, are generally broken down over time through physical processes, but under natural conditions, they can remain intact in the environment for centuries without posing a significant threat to ecosystems. The inability of certain materials to degrade biologically can lead to ecological imbalances, as they may not only persist but also accumulate to harmful levels in ecosystems, affecting biodiversity and nutrient cycles. Which of the following statements are correct?
Which of the following cell organelles of the leaf contain chlorophyll pigments? 1. Cuticule 2. Epidermis 3. Guard cells 4. Chloroplast
In an experiment, a straight copper wire is placed parallel to and above a compass needle. The direction of the current is such that when the current flows from north to south through the wire, the compass needle deflects towards the east. What will happen to the deflection of the needle when the direction of current is reversed, i.e., the current flows from south to north through the wire?
In an experiment involving two potted plants placed in separate airtight bell jars, one jar contains potassium hydroxide. After exposure to sunlight, a starch test is conducted. Which of the following statements is FALSE?
Observe the given experimental setup carefully. When the current flows from B to A, the rod is observed to move towards the left. When the current is reversed, the rod moves towards the right. Based on this observation, which of the following best explains the displacement of the rod?
In a cross between two tall pea plants a few dwarf pea plants were also obtained in F1 generation. It is possible only if the gene combination of the parental plants is :
Which of the following options correctly pairs the organism shown in the picture with its method of reproduction?
Which among the following structure is a reproductive structure in Bread mould?
Assertion (A): After fertilization, the petals, sepals, stamens, style, and stigma of a flower usually wither and fall off, while the ovary ripens into a fruit. Reason (R): The ovary protects the developing seed, while the other floral parts are no longer required for reproduction after fertilization.
Three beakers labelled as A, B and C each containing 25 mL of water were taken. A small amount of NaOH, anhydrous CuSO4 and NaCl were added to the beakers A, B and C respectively. It was observed that there was an increase in the temperature of the solutions contained in beakers A and B, whereas in case of beaker C, the temperature of the solution falls. Which one of the following statement(s) is(are) correct? (i) In beakers A and B, exothermic process has occurred. (ii) In beakers A and B, endothermic process has occurred. (iii) In beaker C exothermic process has occurred. (iv) In beaker C endothermic process has occurred
Which of the following correctly categorizes contraceptive methods based on whether they prevent fertilization or not?
Choose the mismatched pair
Which of the following statements is correct regarding ATP?
Which of the following reactions is/are not a decomposition reaction ? i) Reaction of ferrous sulphate to ferric oxide ii) Reaction of copper oxide to copper iii) reaction of ferrous sulphate to copper sulphate iv) reaction of lead nitrate to lead oxide
When barium hydroxide is mixed with ammonium chloride in a test tube, the bottom of the test tube feels cold to the touch. What does this indicate?
In an experiment, hydrogen gas is passed over a heated sample that initially has a black coating. As the reaction proceeds, the black coating turns brown, indicating that the reverse reaction has taken place and copper is formed. Identify the following:X: The chemical compound that constitutes the initial black coating on the heated sample. Y: The substance produced after hydrogen gas reduces X. Which of the following options correctly identifies X and Y?
Assertion (A): The alveoli in the lungs are balloon-like structures that provide a surface for gas exchange. Reason (R): The walls of the alveoli contain an extensive network of blood vessels, facilitating the exchange of .
Which of the following statements are correct? A) A chemical equation represents the reactants, products, and their physical states symbolically and must always be balanced. B) In a combination reaction, a single substance decomposes to form two or more substances. C) Exothermic reactions absorb energy, while endothermic reactions release energy. D) In a displacement reaction, an element displaces another element from its compound.
Which of the following statements is correct regarding metal oxides and their solubility in water?
Which of the following statements about the reaction of metals with water is correct?
Which of the following sequences correctly represents the flow of blood in different animals?
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