Chemical reactions and equations
Chapter 3: Chemical reactions and equations
- Identify from the following reactions the reactants that undergo oxidation and reduction A. Fe + S → FeS Here , Fe is oxidised from 0 to +2, while S is reduced from 0 to -2 Fe undergoes oxidation (as losing electrons) Sulphur und... 1
- 5. Observe the following picture a write down the chemical reaction with explanation. The picture given shows the corrosion of iron. The chemical formula of rust is Fe₂O₃.H₂O. The rust on iron does not form by a simple reactio... 1
- d. It is recommended to use air tight container for storing oil for long time It is recommended to use air tight container for storing oil for long time because, When oil comes in contact with air, it undergoes oxidati... 1
- c.While preparing dilute sulphuric acid from concentrated sulphuric acid in the laboratory, While preparing dilute sulphuric acid from concentrated sulphuric acid in the laboratory, the concentrated sulphuric acid is added slowly to... 1
- b. It takes time for pieces of Shahabad tile to disappear in HCl, but its powder disappears rapidly When HCl is added to Shahabad stone effervescence of CO₂ is formed. The CO₂effervescence is formed slowly with the pieces of Shahabad tiles... 1
- a.When the gas formed on heating limestone is passed through freshly prepared lime water, the lime water turns milky i. When limestone (CaCO₃) is heated; it undergoes decomposition reaction giving calcium oxide (CaO) and carbon dioxide (CO₂) as products. ii... 1
- d. Displacement reaction 3. Explain the following terms with examples. The reaction in which the place of the ion of a less reactive element in a compound is taken by another more reactive element by formation o... 1
- c. Balanced equation 3. Explain the following terms with examples. A chemical equation in which the number of atoms of the elements in the reactant is same as the number of atoms of the elements in the produ... 1
- b. Combination reaction 3. Explain the following terms with examples. When two or more reactants combine in a reaction to form a single product, it is called a combination reaction. Example:: When HCl vapours s... 1
- Endothermic reaction Endothermic reaction: In endothermic reaction, heat is either absorbed from the surroundings or heat has to supplied from outside. It means... 1
- e. Explain the similarity and difference in two events, namely adding NaOH to water and adding CaO to water. Chemical equations involved: 1) Reaction between NaOH and water NaOH(s)+H2O(l)->Na^+_((aq)) + OH^-_((aq)) + triangle (HEAT) 2) Reaction betw... 1
- d. Explain the types of reaction with reference to oxygen and hydrogen. Illustrate with examples. There are main three types of chemical reactions with reference to oxygen and hydrogen: 1.Combination Reaction 2. Decomposition Reaction 3.... 1
- c. Explain the term reactant and product giving examples. Reactants:- The substances which take part in a chemical reaction are called reactants. Products:-The substances which are formed due to the... 2
- b. How can the rate of the chemical reaction, namely, decomposition of hydrogen peroxide be increased? The rate of chemical reaction can be increased by using catalysts. In hydrogen peroxide decomposition, (Manganese dioxide powder)MnO₂ is use... 1
- a. What is the reaction called when oxidation and reduction take place simultaneously? When oxidation and reduction takes place simultaneously, the reaction is called redox reaction. Oxidation: losing of electrons Reduction: ga... 1
- 1. Choose the correct option from the bracket and explain the statement giving reason. (Oxidation, displacement a. To prevent rusting, a layer of zinc metal is applied on iron sheets. Reason :: In this method, a thin layer of zinc is applied on iron sh... 1