Chemical Reactions and Equations: Class 10 Science Q&A · Page 2
29 free answers on Chemical Reactions and Equations (Science) for Class 10 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- ScienceClass 10CBSE
Identify the substances that are oxidised and that are reduced in the following equation.
i) 4Na(s) + O2(g) → 2Na2O(s) ii) CuO(s) + H2(g) → Cu(s) + H2O(l) Solution: The Sodium (Na) in the first equation is getting oxidized with the addition of Oxygen (O2), and the Copper (Cu) in the second equation is reduced due to the addition of Hydrogen (H2).
- ScienceClass 10CBSE
Give an example of a double displacement reaction other than the one given in Activity 1.10.
Reaction Between silver nitrate (AgNO3) and Sodium chloride (NaCl) is an example of a double displacement reaction. During the reaction, negative and positive ions trade positions as a result of the formation of white silver chloride precipitate. The chemical reaction is given below. Ag+ + NO3– + Na+ + Cl– → AgCl + Na+ + NO3–
- ScienceClass 10CBSE
Why does the colour of copper sulphate solution change when an iron nail is dipped in it?
When an iron nail is dipped in the copper sulphate solution, iron displaces copper from the copper sulphate because iron is more reactive than copper. Therefore, the colour of the copper sulphate solution changes. The reaction is Fe + CuSO4 → FeSO4 + Cu
- ScienceClass 10CBSE
Why is the amount of gas collected in one of the test tubes in Activity 1.7 double the amount collected in the other? Name this gas.
In activity 1.7, gas collected in one of the test tubes is double of the amount collected in the other because water gets hydrolysed to release H2 and O2 gas. Here, after electrolysis two molecules of Hydrogen and one molecule of oxygen gas are released; hence, the amount of Hydrogen collected would be double than that of oxygen.
- ScienceClass 10CBSE
Write a balanced chemical equation with state symbols for the following reactions i) Solutions of Barium chloride and Sodium sulphate in water react to give insoluble Barium sulphate and solution of Sodium chloride. ii) Sodium hydroxide solution in water reacts with the hydrochloric acid solution to produce Sodium chloride solution and water.
Solution: i) BaCl2 + Na2SO4 → BaSO4 + 2NaCl ii) NaOH + HCl → NaCl + H2O In-text questions set 2 Page number – 10 A solution of a substance, ‘X,’ is used for whitewashing. (i) Name the substance ‘X’ and write its formula.</s
- ScienceClass 10CBSE
Why should a magnesium ribbon be cleaned before burning in the air?
Magnesium ribbon should be cleaned before burning in air because Magnesium metal reacts with the atmospheric oxygen and forms Magnesium Oxide (MgO) layer which is a very stable compound. In order to prevent further reactions with Oxygen, it is therefore necessary to clean the ribbon by to remove the layer of MgO. Write a balanced equation for the following chemical reactions. i) Hydrogen + Chloride —-> Hydrogen chloride</st
- ScienceClass 10All
What kind of reaction is Ca(II) HCl → CaCl2 H2
The notation "Ca(II)" in this equation appears to be indicating calcium in the +2 oxidation state, though it's unusual formatting. Assuming the intended reaction is Ca + 2HCl → CaCl2 + H2, this is a single replacement reaction (single displacement) where calcium metal displaces hydrogen from hydrochloric acid. In this reaction, elemental calcium replaces hydrogen in the acid, forming calcium chloride salt and releasing hydrogen gas as products. This is also a redox reaction, with calcium
- ScienceClass 10All
What are the products of the following reaction: CaH2(s) 2H2O(l) →
The products of the reaction CaH2(s) + 2H2O(l) → are calcium hydroxide (Ca(OH)2) and hydrogen gas (H2), giving the complete balanced equation: CaH2(s) + 2H2O(l) → Ca(OH)2(aq) + 2H2(g). Calcium hydride, a white crystalline solid, reacts vigorously with water in what's classified as a hydrolysis reaction (literally "breakdown by water"). In this reaction, the hydride ions (H-) from calcium hydride act as strong bases, pulling protons from water molecules to form hydrogen gas, while th
- ScienceClass 10All
Which statement is true about this reaction: C6H12O6 6O2 → 6CO2 6H2O
The true statements about the reaction C6H12O6 + 6O2 → 6CO2 + 6H2O include: (1) it represents cellular respiration or glucose combustion, (2) it is an exothermic reaction that releases energy, (3) it is a redox reaction where glucose is oxidized and oxygen is reduced, (4) the carbon in glucose increases in oxidation state while oxygen decreases, and (5) this is essentially the reverse of photosynthesis. This reaction breaks down high-energy glucose molecules using oxygen to produce lower