Chemical Reactions and Equations

Fe2O3 + 2Al → Al2O3 + 2Fe The above reaction is an example of a (i)Combination reaction (ii)Double displacement reaction (iii)Decomposition reaction (iv)Displacement reaction Solution:

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(iv)Displacement reaction Reason: To create aluminium oxide, oxygen from ferrous oxide is transferred to aluminium metal. Aluminum is a more reactive metal than Fe in this reaction. Al will therefore remove Fe from its oxide. One of the elements displaces another in a chemical process known as a displacement reaction. More reactive metal here replaces …

Fe2O3 + 2Al → Al2O3 + 2Fe The above reaction is an example of a (i)Combination reaction (ii)Double displacement reaction (iii)Decomposition reaction (iv)Displacement reaction Solution: Read More »

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 the above

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(j) (a) and (b) Explanation: (a) Because oxygen is being removed . and (b) Because the elemental Carbon is being given more oxygen removed from Lead.

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)

Leave a Comment / Chemical Reactions and Equations / By UP Gupta

(i)With the addition of oxygen (O2) in the first equation, the sodium (Na) gets oxidised, and O2 is reduced. (ii) In the second equation CuO is reduced and hydrogen (H2) is oxidised.

Give an example of a double displacement reaction other than the one given in Activity 1.10.

Leave a Comment / Chemical Reactions and Equations / By UP Gupta

A double displacement reaction can be seen between sodium chloride (NaCl) and silver nitrate (AgNO3). Due to the production of a white silver chloride precipitate, positive and negative ions exchange places during the reaction. The chemical reaction is given below. AgNO3 + NaCl → AgCl (ppt) + NaNO3

Why does the colour of copper sulphate solution change when an iron nail is dipped in it?

Leave a Comment / Chemical Reactions and Equations / By UP Gupta

Because iron is more reactive than copper, it displaces copper from the copper sulphate solution when an iron nail is dipped in the solution. As a result, the copper sulphate solution’s colour changes. The result is Fe + CuSO4 → FeSO4 + Cu

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.

Leave a Comment / Chemical Reactions and Equations / By UP Gupta

Because water is hydrolyzed to release H2 and O2 gas in activity 1.7, the amount of gas collected in one test tube is double that of the other. Here, two molecules of hydrogen and one molecule of oxygen are released as a result of electrolysis; as a result, there will be twice as much hydrogen …

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. Read More »

A solution of a substance, ‘X,’ is used for whitewashing.
(i) Name the substance ‘X’ and write its formula.
(ii) Write the reaction of the substance ‘X’ named in (i) above with water.

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(i) The substance ‘X’ which is used in whitewashing is quick lime or Calcium Oxide (CaO). (ii) CaO + H2O → Ca(OH)2

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.

Leave a Comment / Chemical Reactions and Equations / By UP Gupta

(i) BaCl2 + Na2SO4 → BaSO4 + 2NaCl (ii) NaOH + HCl → NaCl + H2O

Write a balanced equation for the following chemical reactions.
(i) Hydrogen + Chloride —-> Hydrogen chloride
(ii) Barium chloride + Aluminium sulphate —-> Barium sulphate + Aluminium chloride
(iii) Sodium + Water —-> Sodium hydroxide + Hydrogen

Leave a Comment / Chemical Reactions and Equations / By UP Gupta

(i) H2 + Cl2 → 2HCl (ii) 3BaCl2 + Al2(SO4)3 →3BaSO4 + 2AlCl3 (iii) 2Na + 2H2O → 2NaOH + H2

Why should a magnesium ribbon be cleaned before burning in the air?

Leave a Comment / Chemical Reactions and Equations / By JSIERT

Magnesium metal reacts with air oxygen to generate magnesium oxide (MgO), a very stable chemical, hence magnesium ribbon needs to be cleaned before burning in the air. Therefore, it is necessary to clean the ribbon by removing the layer of MgO in order to prevent further reactions with oxygen