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Life Processes Questions and Answers 1. The kidneys in human beings are a part of the system for (a) nutrition. (b) respiration. (c) excretion. (d) transportation. Answer: (c) excretion. 2. The xylem in plants are responsible for (a) transport of water. (b) transport of food. (c) transport of amino acids. (d) transport of oxygen. Answer: (a) transport of water. 3. The autotrophic mode of nutrition requires (a) carbon dioxide and water. (b) chlorophyll. (c) sunlight. (d) all of the above. Answer: (d) all of the above. 4. The breakdown of pyruvate to give carbon dioxide, water and energy takes place in (a) cytoplasm. (b) mitochondria. (c) chloroplast. (d) nucleus. Answer: (b) mitochondria. 5. How are fats digested in our bodies? Where does this process take place? Fats are emulsified by bile salts in the small intestine, breaking large globu...

Science Answers Answers to Science Questions 1. Which of the following is a plant hormone? (a) Insulin (b) Thyroxin (c) Oestrogen (d) Cytokinin. Answer: (d) Cytokinin. 2. The gap between two neurons is called a (a) dendrite. (b) synapse. (c) axon. (d) impulse. Answer: (b) synapse. 3. The brain is responsible for (a) thinking. (b) regulating the heart beat. (c) balancing the body. (d) all of the above. Answer: (d) all of the above. 4. What is the function of receptors in our body? Think of situations where receptors do not work properly. What problems are likely to arise? Answer: Receptors detect changes in the environment and send signals to the brain. If they don’t work properly, problems like inability to feel pain, temperature, or touch, and difficulty in responding to stimuli may arise. 5. Draw the structure of a neuron and explain its function. Answer: [Imagine a neuron with a cell body, dendrites, axon...

Science Answers Answers to Science Questions 1. Ethane, with the molecular formula C₂H₆, has (a) 6 covalent bonds. (b) 7 covalent bonds. (c) 8 covalent bonds. (d) 9 covalent bonds. Answer: (a) 6 covalent bonds. 2. Butanone is a four-carbon compound with the functional group (a) carboxyl acid. (b) aldehyde. (c) ketone. (d) alcohol. Answer: (c) ketone. 3. While cooking, if the bottom of the vessel is getting blackened on the outside, it means that (a) the food is not cooked completely. (b) the fuel is not burning completely. (c) the fuel is wet. (d) the fuel is burning completely. Answer: (b) the fuel is not burning completely. 4. Explain the nature of the covalent bond using the bond formation in CH₄. Answer: In CH₄ (methane), a covalent bond forms when carbon shares its four valence electrons with four hydrogen atoms. Each carbon-hydrogen bond is created by the sharing of electron pairs, resulting in a stable molec...

Science Answers Answers to Science Questions 1. Which of the following pairs will give displacement reactions? (a) NaCl solution and copper metal (b) MgCl₂ solution and aluminium metal (c) FeSO₄ solution and silver metal (d) AgNO₃ solution and copper metal Answer: (d) AgNO₃ solution and copper metal 2. Which of the following methods is suitable for preventing an iron frying pan from rusting? (a) Applying grease (b) Applying paint (c) Applying a coating of zinc (d) All of the above. Answer: (d) All of the above. 3. An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be (a) calcium (b) carbon (c) silicon (d) iron Answer: (a) calcium 4. Food cans are coated with tin and not with zinc because (a) zinc is costlier than tin. (b) zinc has a higher melting point than tin. (c) zinc is more reactive than tin. (d) zinc is less re...

Science Answers Answers to Science Questions 1. A solution turns red litmus blue. Is pH likely to be (a) 1 (b) 4 (c) 5 (d) 10 Answer: (d) 10 2. A solution reacts with crushed egg-shells to give a gas that turns lime-water milky. The solution contains Answer: HCl 3. 10 mL of a solution of NaOH is found to be completely neutralised by 8 mL of a given solution of HCl. If we take 20 mL of the same solution of NaOH, the amount of HCl solution (the same solution as before) required to neutralise it will be (a) 4 mL (b) 8 mL (c) 12 mL (d) 16 mL Answer: (d) 16 mL 4. Which one of the following types of medicines is used for treating indigestion? (a) Antibiotic (b) Analgesic (c) Antacid (d) Antiseptic Answer: (c) Antacid 5. Write word equations and then balanced equations for the reaction taking place when- (a) dilute sulphuric acid reacts with zinc granules. Word equation: Sulphuric acid + Zinc → Zinc sulphate + Hydrogen Balanced equatio...

Class 10 Chemical Reactions and Equations - Full Questions and Answers Class 10 Chemical Reactions and Equations - Full Questions and Answers 1. Which of the statements about the reaction below are incorrect? 2PbO(s) + C(s) → 2Pb(s) + CO₂(g) (a) Lead is getting reduced. (b) Carbon dioxide is getting oxidised. (c) Carbon is getting oxidised. (d) Lead oxide is getting reduced. (i) (a) and (b) (ii) (a) and (c) (iii) (a), (b) and (c) (iv) all Answer: (i) (a) and (b) are incorrect. 2. Fe₂O₃ + 2Al → Al₂O₃ + 2Fe The above reaction is an example of a (a) combination reaction. (b) double displacement reaction. (c) decomposition reaction. (d) displacement reaction. Answer: (d) displacement reaction. 3. What happens when dilute hydrochloric acid is added to iron fillings? Tick the correct answer. (a) Hydrogen gas and iron chloride are produced. (b) Chlorine gas and iron hydr...

Class 10 Chemical Reactions and Equations - Notes Class 10 Chemical Reactions and Equations - Notes 1. Which of the statements about the reaction below are incorrect? Answer: (i) (a) and (b) are incorrect. 2. Fe 2 O 3 + 2Al → Al 2 O 3 + 2Fe Answer: (d) displacement reaction. 3. What happens when dilute hydrochloric acid is added to iron fillings? Tick the correct answer. Answer: (a) Hydrogen gas and iron chloride are produced. 4. What is a balanced chemical equation? Why should chemical equations be balanced? Answer: A balanced chemical equation has the same number of atoms of each element on both sides. Equations should be balanced to follow the law of conservation of mass. 5. Translate the following statements into chemical equations and then balance them. (a) N 2 + 3H 2 → 2NH 3 (b) 2H 2 S + 3O 2 → 2H 2 O + 2SO 2 (c) 3BaCl 2 + Al 2 (SO 4 ) 3 → 2AlCl 3 + 3BaSO 4 (d) 2K + 2H 2 O → 2KOH + H 2 ...