Question 1: Identify ‘p’, ‘q’, and ‘r’ in the following balanced reaction

Reaction: p Pb (NO3)2(s)→Heatq PbO(s)+r NO2(g)+O2(g)\text{p Pb (NO}_3)_2(s) \xrightarrow{\text{Heat}} \text{q PbO(s)} + \text{r NO}_2(g) + O_2(g)

Options:

  • A. 2, 2, 4
  • B. 2, 4, 2
  • C. 2, 4, 4
  • D. 4, 2, 2

Solution: We need to balance the chemical reaction for the decomposition of lead nitrate. The balanced chemical equation is:

2Pb(NO3)2(s)→Heat2PbO(s)+4NO2(g)+O2(g)2 \text{Pb(NO}_3)_2(s) \xrightarrow{\text{Heat}} 2 \text{PbO(s)} + 4 \text{NO}_2(g) + O_2(g)

Thus, p = 2, q = 2, r = 4.

Answer: B. 2, 4, 2

Question 2: Match column I with column II and select the correct option

Column I:

  • a. A metal that forms amphoteric oxides
  • b. A metal which melts when kept on our palm
  • c. A metal that reacts with nitric acid
  • d. A metal which cannot displace hydrogen from acids

Column II:

  • (i) Ga
  • (ii) Au
  • (iii) Al
  • (iv) Mn

Options:

  • A. a – (ii), b – (i), c – (iii), d – (iv)
  • B. a – (iii), b – (i), c – (iv), d – (ii)
  • C. a – (iv), b – (ii), c – (iii), d – (i)
  • D. a – (iii), b – (ii), c – (i), d – (iv)

Solution:

  • a. Amphoteric oxides: Aluminium (Al) and Gallium (Ga) form amphoteric oxides. However, Ga is less well known for this property compared to Al. So, a → (iii).
  • b. Metal that melts on the palm: Gallium (Ga) melts at a low temperature and can melt on the palm. Thus, b → (i).
  • c. Metal that reacts with nitric acid: Manganese (Mn) reacts with nitric acid to release hydrogen gas. So, c → (iv).
  • d. Metal that cannot displace hydrogen from acids: Gold (Au) is inert and cannot displace hydrogen. Therefore, d → (ii).

Answer: B. a – (iii), b – (i), c – (iv), d – (ii)

Question 3: The solution in the given figure is likely to be

Options:

  • A. HNO3
  • B. C2H5OH
  • C. H2SO4
  • D. CO2 in water

Solution: This question requires visual interpretation, which isn’t possible in this format. However, in general, HNO3 is a strong acid, H2SO4 is another strong acid, C2H5OH is ethanol (an alcohol), and CO2 in water forms carbonic acid. Without the image, this question can be challenging to answer accurately.

Question 4: The solution in the given scenario turns phenolphthalein pink. On addition of solution B, the pink color disappears. Which of the following statements is true for solutions A and B?

Options:

  • A. A is strongly basic and B is a weak base.
  • B. A is strongly acidic and B is a weak acid.
  • C. A has a pH greater than 7 and B has a pH less than 7.
  • D. A has a pH less than 7 and B has a pH greater than 7.

Solution: Phenolphthalein turns pink in basic solutions and becomes colorless in acidic solutions. Since the solution turns pink first and then loses the color on adding solution B, solution A is basic and solution B is acidic.

Answer: D. A has a pH less than 7 and B has a pH greater than 7.

Question 5: When 50g of lead powder is added to 300 ml of blue copper sulfate solution, after a few hours, the solution becomes colorless. This is an example of

Options:

  • A. Combination reaction
  • B. Decomposition reaction
  • C. Displacement reaction
  • D. Double displacement reaction

Solution: This is a typical displacement reaction where lead displaces copper from copper sulfate (CuSO₄) due to its higher reactivity. The reaction is:

Pb(s)+CuSO4(aq)→PbSO4(aq)+Cu(s)\text{Pb(s)} + \text{CuSO}_4(aq) \rightarrow \text{PbSO}_4(aq) + \text{Cu(s)}

Answer: C. Displacement reaction

Question 6: The electronic configuration of three elements X, Y, and Z are:

  • X: 2, 8, 7
  • Y: 2, 8, 2
  • Z: 2, 8

Which of the following is true?

Options:

  • A. Y and Z are metals
  • B. Y and X are non-metals
  • C. X is a non-metal and Y is a metal
  • D. Y is a non-metal and Z is a metal

Solution:

  • X (2, 8, 7) has 7 valence electrons, indicating it is a non-metal (Halogen).
  • Y (2, 8, 2) has 2 valence electrons, indicating it is a metal (Alkaline earth metal).
  • Z (2, 8) has a complete outer shell, indicating it is a noble gas, which is inert.

Thus, X is a non-metal, Y is a metal, and Z is a noble gas.

Answer: C. X is a non-metal and Y is a metal

Question 7: Which of the following is an endothermic reaction?

Options:

  • A. Burning of candle.
  • B. Cooking of food.
  • C. Decomposition of vegetable matter.
  • D. Reaction of sodium with air.

Solution: An endothermic reaction is one that absorbs heat. Among the options, cooking of food requires heat input, making it an endothermic process.

Answer: B. Cooking of food.

Question 8: During cellular oxidation of Glucose, ATP is produced along with formation of other products in this reaction. Which of the following events is associated with the production of maximum ATP molecules per molecule of glucose?

Options:

  • A. Ethanol in yeast
  • B. Lactic acid in muscle cells
  • C. Carbon dioxide in yeast cells
  • D. Carbon dioxide in human cells

Solution: The complete oxidation of glucose in human cells (aerobic respiration) produces the maximum ATP, as it goes through all stages: Glycolysis, Citric Acid Cycle, and Electron Transport Chain.

Answer: D. Carbon dioxide in human cells.

Question 9: During which of the following stages of the circulation of blood in a normal human being, the oxygenated blood is pumped to all parts of the body?

Options:

  • A. Contraction of the left atrium
  • B. Contraction of left ventricle
  • C. Relaxation of the right atrium
  • D. Relaxation of the right ventricle

Solution: The left ventricle pumps oxygenated blood to the entire body through the aorta.

Answer: B. Contraction of left ventricle

Question 10: Which of the following adaptations in herbivores helps in the digestion of cellulose?

Options:

  • A. Longer large intestine
  • B. Smaller large intestine
  • C. Smaller small intestine
  • D. Longer small intestine

Solution: Herbivores have a longer large intestine to allow more time for the digestion of cellulose.

Answer: A. Longer large intestine

Question 11: There was a cerebellar dysfunction in a patient. Which of the following activities will get disturbed as a result of this?

Options:

  • A. Salivation
  • B. Hunger control
  • C. Posture and balance
  • D. Regulation of blood pressure

Solution: The cerebellum is primarily responsible for coordinating voluntary movements, posture, and balance.

Answer: C. Posture and balance

Question 12: In snails, individuals can begin life as male and depending on environmental conditions, they can become female as they grow. This is because:

Options:

  • A. Male snails have dominant genetic makeup.
  • B. Female snails have dominant genetic makeup.
  • C. Expression of sex chromosomes can change in a snail’s lifetime.
  • D. Sex is not genetically determined in snails.

Solution: This phenomenon is due to environmental influences on the sex determination of the snail, where sex can change during the course of its life.

**Answer: C. Expression of sex chromosomes can change in a

snail’s lifetime.**

Question 13: Which of the following statements regarding the process of photosynthesis is true?

Options:

  • A. Photosynthesis occurs in the mitochondria of the plant cell.
  • B. Oxygen is released during the light-dependent reaction of photosynthesis.
  • C. Carbon dioxide is released during the light-independent reaction.
  • D. Photosynthesis produces both glucose and oxygen.

Solution: Photosynthesis involves light-dependent and light-independent reactions, where glucose and oxygen are produced.

Answer: D. Photosynthesis produces both glucose and oxygen.

Certainly! Here are the answers and explanations for the remaining questions:

Question 14: The plant tissue responsible for the transport of water and minerals is:

Options:

  • A. Phloem
  • B. Xylem
  • C. Cortex
  • D. Pith

Solution: The xylem is responsible for the transport of water and minerals from the roots to the rest of the plant.

Answer: B. Xylem

Question 15: Which of the following cells are responsible for the formation of antibodies?

Options:

  • A. RBCs
  • B. Platelets
  • C. B-lymphocytes
  • D. T-lymphocytes

Solution: B-lymphocytes are responsible for the production of antibodies in the immune system.

Answer: C. B-lymphocytes

Question 16: Which one of the following is the correct function of a root hair?

Options:

  • A. Absorbs water and minerals
  • B. Synthesizes food
  • C. Stores starch
  • D. Transports water

Solution: Root hairs are specialized for absorbing water and minerals from the soil.

Answer: A. Absorbs water and minerals

Question 17: Which of the following processes is an example of passive transport?

Options:

  • A. Active transport
  • B. Endocytosis
  • C. Diffusion
  • D. Exocytosis

Solution: Diffusion is an example of passive transport, where substances move from a region of higher concentration to a region of lower concentration without the use of energy.

Answer: C. Diffusion

Question 18: What is the main product of the process of fermentation in yeast?

Options:

  • A. Water
  • B. Alcohol
  • C. Oxygen
  • D. Carbon dioxide

Solution: In yeast, fermentation produces alcohol (ethanol) and carbon dioxide as the main products. However, alcohol is the primary product of interest in this case.

Answer: B. Alcohol

Question 19: In humans, which of the following is NOT a component of the circulatory system?

Options:

  • A. Blood
  • B. Heart
  • C. Lungs
  • D. Blood vessels

Solution: While the lungs are essential for respiration and gas exchange, they are not considered part of the circulatory system, which includes blood, heart, and blood vessels.

Answer: C. Lungs

Question 20: Which of the following is an example of asexual reproduction?

Options:

  • A. Pollination
  • B. Budding
  • C. Fertilization
  • D. Cross-pollination

Solution: Budding is a form of asexual reproduction where a new organism grows from a bud on the parent organism.

Answer: B. Budding

Question 21: Which of the following parts of the brain is responsible for controlling voluntary movements?

Options:

  • A. Medulla oblongata
  • B. Cerebrum
  • C. Cerebellum
  • D. Spinal cord

Solution: The cerebrum is responsible for controlling voluntary movements, as well as higher cognitive functions.

Answer: B. Cerebrum

Question 22: The largest gland in the human body is:

Options:

  • A. Liver
  • B. Pancreas
  • C. Skin
  • D. Thyroid

Solution: The liver is the largest gland in the human body and is involved in detoxification, protein synthesis, and bile production.

Answer: A. Liver

Question 23: The primary source of energy for living organisms is:

Options:

  • A. Water
  • B. Sunlight
  • C. Oxygen
  • D. Food

Solution: The primary source of energy for most living organisms is sunlight, which is captured by plants during photosynthesis.

Answer: B. Sunlight

Question 24: Which of the following vitamins is essential for the proper functioning of the retina of the eye?

Options:

  • A. Vitamin A
  • B. Vitamin B
  • C. Vitamin C
  • D. Vitamin D

Solution: Vitamin A is essential for the proper functioning of the retina of the eye and helps in night vision.

Answer: A. Vitamin A

Question 25: Which of the following is a non-renewable resource?

Options:

  • A. Wind energy
  • B. Solar energy
  • C. Natural gas
  • D. Biomass

Solution: Natural gas is a non-renewable resource, as it cannot be replenished in a human timescale. Other options like wind, solar, and biomass are renewable.

Answer: C. Natural gas

Question 26: What is the role of chlorophyll in photosynthesis?

Options:

  • A. Absorbs light energy
  • B. Converts oxygen into carbon dioxide
  • C. Helps in the formation of glucose
  • D. Provides energy for the plant

Solution: Chlorophyll absorbs light energy from the sun and converts it into chemical energy during photosynthesis.

Answer: A. Absorbs light energy

Question 27: Which of the following is an example of a physical change?

Options:

  • A. Rusting of iron
  • B. Burning of paper
  • C. Melting of ice
  • D. Cooking of an egg

Solution: Melting of ice is a physical change, as the substance (water) does not change its chemical composition; it simply changes its state from solid to liquid.

Answer: C. Melting of ice

Question 28: Which of the following gases is responsible for the greenhouse effect?

Options:

  • A. Oxygen
  • B. Nitrogen
  • C. Carbon dioxide
  • D. Hydrogen

Solution: Carbon dioxide (CO₂) is a major greenhouse gas that traps heat in the Earth’s atmosphere, contributing to global warming.

Answer: C. Carbon dioxide

Question 29: The process of digestion of food begins in which part of the human digestive system?

Options:

  • A. Mouth
  • B. Stomach
  • C. Small intestine
  • D. Large intestine

Solution: The process of digestion begins in the mouth, where food is mechanically broken down by chewing and chemically broken down by enzymes in saliva.

Answer: A. Mouth

Question 30: Which of the following is a feature of a monocot plant?

Options:

  • A. Presence of two cotyledons
  • B. Parallel venation in leaves
  • C. Vascular bundles arranged in a ring
  • D. Presence of a taproot system

Solution: Monocots have parallel venation in their leaves, unlike dicots, which have reticulate venation.

Answer: B. Parallel venation in leaves