Chemical Reactions and Equations
CBSE Class 10 Science · every board question from this chapter, 2023–2026
- Given below is a diagrammatic representation of cross-section of a leaf: (i) Identify 'P' in the given diagram and write down its…2026
- Draw a labelled diagram showing open and closed stomatal pore. List the main events that occur during the process of photo-…2026
- Which of the following is an example of a displacement reaction?2026
- Which of the following are combination reactions? (i) 2 KClO_3 → 2 KCl+3 O_2 (ii) MgO+H_2 O → Mg(OH)_2 (iii) 4 Al+3 O_2 → 2 Al_2…2026
- When lead nitrate is heated in a boiling tube, we observe:2026
- (i) AgNO_3+NaCl → NaNO_3+AgCl (ii) K_2 SO_4+BaCl_2 → BaSO_4+2 KCl Which of the following options clearly describes both the…2026
- C_6 H_12 O_6(aq)+6 O_2( g) → 6 CO_2( g)+6 H_2 O_(l). The above reaction is an example of -2026
- When ferrous sulphate crystals are heated in a test tube, we observe that:2026
- Which of the following are decomposition reactions? (i) 2 KClO_3 → 2 KCl+3 O_2 (ii) MgO+H_2 O → Mg(OH)_2 (iii) 2 H_2 O → H_2+O_2…2026
- The gases evolved on heating lead (II) nitrate crystals are:2026
- In the question two statements are given - one labelled as Assertion and other labelled as Reason (R). Answer this question…2026
- Read the following passage and answer the questions that follow: One student was comparing the reactivity of different metals for…2026
- Write balanced equations for the reactions of the following: 2 × 1=2 Iron with steam Calcium with water2026
- Answer the following: Why should chemical equations be balanced? Name the oxidising and reducing agent in the following equation:…2026
- Write the balanced chemical equation for the preparation of: Sodium hydroxide by electrolysis of brine solution Sodium carbonate2026
- Name the substance oxidised and reduced in the following reaction: ZnO+C → Zn+CO Balance the following chemical reaction:…2026
- Define the following terms: 3 × 1=3 (i) Corrosion (ii) Rancidity (iii) Exothermic reaction2026
- What happens when (i) potassium iodide solution is added to lead (II) nitrate solution? (ii) zinc is added to copper (II)…2026
- Answer the following: Identify the substance oxidized and the substance reduced in the following reaction: 4 Na+O_2 → 2 Na_2 O…2026
- Account for the following: White silver chloride turns grey when exposed to sunlight. Lead (II) nitrate on heating releases brown…2026
- What happens when (i) lead (II) nitrate is heated? (ii) iron (II) sulphate is heated? (iii) silver chloride is exposed to…2026
- What happens when (i) Calcium carbonate is heated? (ii) Silver bromide is exposed to sunlight? (iii) Lead is added to copper (II)…2026
- 2 g of green coloured crystals of ferrous sulphate are heated in a dry boiling tube. Name the type of chemical reaction taking…2026
- What happens when: An iron nail is dipped in copper (II) sulphate solution? Potassium iodide solution is mixed with lead nitrate…2026
- Translate the following statements into chemical equation and then balance them: Water is added to quicklime Burning of natural…2026
- Seema took a small amount of copper powder in a china dish and heated it. What changes will she observe on heating? When H_2 gas…2026
- Answer the following: 3 × 1=3 Write two observations when green coloured crystals of ferrous sulphate are heated in a boiling…2026
- Define the following terms: 3 × 1=3 Corrosion Rancidity Double displacement reaction2026
- Read the following passage and answer the questions that follow: In the given diagram, when electricity is passed through an…2026
- Example of thermal decomposition reaction are (i) 2 AgCl → 2 Ag+Cl_2 (ii) CaCO_3 → CaO+CO_2 (iii) 2 H_2 O → 2 H_2+O_2 (iv) 2…2025
- The main observations while performing the experiment of burning magnesium ribbon in air are: (i) Magnesium ribbon burns with a…2025
- In which one of the following situations a chemical reaction does not occur?2025
- Electrolysis of water is a decomposition reaction. The mass ratio (M_H: M_O) of hydrogen and oxygen gases liberated at the…2025
- Consider the following chemical equation: pAl+q H_2 O → rAl_2 O_3+s H_2 To balance this chemical equation, the values of 'p',…2025
- The correct balanced chemical equation showing exothermic reaction in which natural gas burns in air is:2025
- Select from the following a statement which is not true about burning of magnesium ribbon in air:2025
- The colour of the solution observed after about 1 hour of placing iron nails in copper sulphate solution is2025
- When a mixture of baking soda and tartaric acid is heated (or mixed in water) a product 'X' is formed, which is responsible for…2025
- The values of a, b, c and d in the following balanced chemical equation are respectively: a Pb(NO_3)_2 → heat b PbO+c NO_2+d O_22025
- Assertion: All exothermic reactions are accompanied with evolution of heat and light. Reason (R): Combination reactions may or…2025
- Assertion: Silver chloride turns grey in sunlight. Reason (R): Decomposition of silver chloride into silver and chlorine takes…2025
- Assertion: Decomposition reactions are generally endothermic reactions. Reason (R): Decomposition of organic matter into compost…2025
- While burning a magnesium ribbon in air, list two safety measures which should be followed. Also state two observations of this…2025
- Name the compound used in black and white photography. State whether the reaction that occurs is exothermic or endothermic. Give…2025
- Balance the following chemical equations: CO_2+H_2 O →[ Chlorophyll ] Sunlight C_6 H_12 O_6+O_2+H_2 O Pb(NO_3)_2 → Heat…2025
- A student performs the following experiment in his school laboratory. List two observations to justify that in this experiment a…2025
- Define oxidation. Identify and name the substance oxidised in the following reaction: CuO+H_2 → Cu+H_2 O2025
- List the possible sources of energy required in decomposition reactions. Illustrate any one with a suitable example. OR What is…2025
- A copper wire on burning in flame, gets coated with a black substance. Write the chemical equation of the reaction that takes…2025
- What happens when: (write balanced chemical equation) Lead nitrate is thermally decomposed, Natural gas burns in oxygen (or air)?2025
- Translate the following statements into chemical equations and then balance them: Nitric acid reacts with calcium hydroxide to…2025
- Write chemical equation for the chemical reaction between the aqueous solutions of sodium sulphate and barium chloride. State two…2025
- Why do we balance a chemical equation? Name and state the law that suggests the balancing of a chemical equation? Balance the…2025
- State the change that is observed when a China dish containing copper powder is heated over the flame of a burner. Name the…2025
- Write balanced chemical equation for the reactions that occur when steam is passed over red hot iron. natural gas is burnt in…2025
- How is a double displacement reaction different from a displacement reaction? Explain giving example in the form of balanced…2025
- (i) Define the term decomposition reaction. Write one chemical equation each for decomposition reaction where energy is supplied…2025
- Zn+2 CH_3 COOH →(CH_3 COO)_2 Zn+H_2 The above reaction is a:2024
- Which of the following is not a thermal decomposition reaction?2024
- An iron nail is placed in a solution of copper sulphate. The nail is taken out after 15 minutes. The nail will be found to be…2024
- A chemical reaction in which exchange of ions occurs between the reactants, is known as:2024
- To balance the following chemical equation, the values of the coefficients x, y and z must be respectively: x Zn(NO_3)_2 →Δ y…2024
- When 2 mL of sodium hydroxide solution is added to few pieces of granulated zinc in a test tube and then warmed, the reaction…2024
- Which of the following is a redox reaction, but not a combination reaction?2024
- Select from the following a decomposition reaction in which source of energy for decomposition is light:2024
- Select from the following a process in which a combination reaction is involved:2024
- Which of the following reactions is an endothermic reaction?2024
- Consider the following Chemical equation: aAl_2 O_3+bHCl → cAlCl_3+d H_2 O In order to balance this chemical equation, the values…2024
- The products obtained when Lead nitrate is heated in a boiling tube.2024
- Identify the correct statement about the following reaction: 2 H_2 S+SO_2 → 2 H_2 O+S2024
- Which one of the following reactions is different from the remaining three?2024
- MnO_2+4 HCl → MnCl_2+2 H_2 O+Cl_2 The reaction given above is a redox reaction because in this case:2024
- Copper powder is taken in a china dish and heated over a burner. Name the product formed and state its colour. Write the chemical…2024
- Write the essential conditions for following reaction to take place and name its types: 2 AgCl → 2 Ag+Cl_2 Complete the following…2024
- Name the type of chemical reaction in which calcium oxide reacts with water. Justify your answer by giving balanced chemical…2024
- When a few drops of Barium chloride solution are added to an aqueous solution of Sodium sulphate, a white precipitate is…2024
- Define a decomposition reaction. Write an equation to show thermal decomposition of ferrous sulphate crystals. OR What is meant…2024
- "No precipitation reaction can occur without exchange of ions between the two reactants." Justify this statement giving a…2024
- Give one example of each of the following: (i) Chemical reaction showing evolution of gas. (ii) Change in the colour of the…2024
- When magnesium ribbon is burnt in air, an ash of white colour is produced. Write chemical equation for the reaction giving the…2024
- Translate the following statement into a balanced chemical equation. "When barium chloride reacts with aluminium sulphate,…2024
- Translate the following statements into chemical equations and then balance them: (i) Solution of barium chloride and aluminium…2024
- Answer the following questions in the context of electrolysis of water: Why is this reaction/process called a decomposition…2024
- Write one chemical equation each for the chemical reaction in which the following have taken place: (i) Change in colour (ii)…2024
- Study the experimental set-up shown in the diagram and write chemical equation for the chemical reaction involved. Name and…2024
- Name the chemical reaction that occurs between iron (III) oxide and aluminium metal. Write its balanced chemical equation. Why is…2024
- State any two observations when an electric current is passed through acidulated water, in a container having each electrode…2024
- (i) Define a decomposition reaction. Write chemical equation for the reaction that occurs when lead nitrate is heated strongly in…2024
- What is a chemical reaction? Describe one activity each to show that a chemical change has occurred in which (i) change of…2024
- When lead nitrate is heated strongly in a boiling tube, two gases are liberated and a solid residue is left behind in the test…2024
- To balance the following chemical equation the values of x and y should respectively be: 2 NaOH+x Al_2 O_3 → yNaAlO_2+H_2 O2023
- Select the appropriate state symbols of the products given as X and Y in the following chemical equation by choosing the correct…2023
- The balanced chemical equation showing reaction between quicklime and water is:2023
- When aqueous solutions of potassium iodide and lead nitrate are mixed, an insoluble substance separates out. The chemical…2023
- The emission of brown fumes in the given experimental set-up is due to2023
- MnO_2+x HCl → MnCl_2+y H_2 O+z Cl_2 In order to balance the above chemical equation, the values of x, y and z respectively are:2023
- A metal ribbon'X'burns in oxygen with a dazzling white flame forming a white ash'Y'. The correct description of X, Y and the type…2023
- Study the following chemical reaction: 2 Na( s)+2 H_2 O(l) → 2 NaOH(aq)+H_2( g) ↑ The reducing agent in this reaction is:2023
- In order to balance the following chemical equation, the values of the coefficients x and y respectively are: x Pb(NO_3)_2 → Heat…2023
- Select the appropriate state symbols of the products given as X and Y in the following chemical equation by choosing the correct…2023
- Consider the following chemical equation I and II I. Mg+2 HCl → MgCl_2+H_2 II. NaOH+HCl → NaCl+H_2 O The correct statement about…2023
- Assertion: Reaction of Quicklime with water is an exothermic reaction. Reason (R): Quicklime reacts vigorously with water…2023
- State whether the given chemical reaction is a redox reaction or not. Justify your answer. MnO_2+4 HCl → MnCl_2+2 H_2 O+Cl_22023
- A metal nitrate 'A' on heating gives a metal oxide along with evolution of a brown coloured gas 'B' and a colourless gas, which…2023
- What is observed when aqueous solutions of potassium iodide and lead nitrate are mixed together? Name the type of reaction and…2023
- Define a double displacement reaction. Write the chemical equation of a double displacement reaction which is also a (i)…2023
- (i) While electrolysing water before passing the current some drops of an acid are added. Why? Name the gases liberated at…2023
- Identify the reducing agent in the following reactions: (i) 4 NH_3+5 O_2 → 4 NO+6 H_2 O (ii) H_2 O+F_2 → HF+HOF (iii) Fe_2 O_3+3…2023
- Define oxidation. Identify the oxidising agent in the following reactions and balance the chemical equations: (i) Pb_3 O_4+HCl →…2023
- Write down the balanced chemical equations for the following reactions and identify the type of reaction in each case. Nitrogen…2023
- Silver chloride kept in a china dish turns grey in sunlight. Write the colour of silver chloride when it was kept in the china…2023
- With the help of suitable chemical equations, list the two main differences between roasting and calcination. How is metal…2023
- With the help of an appropriate example, justify that some of the chemical reactions are determined by Change in temperature,…2023
- A reddish brown metal used in electrical wires when powdered and heated strongly turns black. When hydrogen gas is passed over…2023
- State the change in colour observed in each of the following cases mentioning the reason: Silver chloride is exposed to sunlight.…2023
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