How would you justify that a chemical reaction has taken place in the following cases:
(i)    Burning of magnesium ribbon in air.
(ii)    Addition of lead nitrate solution to potassium iodide solution.
(iii)    Addition of dilute hydrochloric acid to zinc granules.

Balance the following skeleton equations:
(i)    KClO₃ →KCl + O₂
(ii)    Na₂CO₃ + HCl → NaCl + H₂O + CO₂
(iii)    CH₄ + O₂ → CO₂ + H₂O
(iv)    NaCl + H₂SO₄ → Na₂SO₄ + HCl
(v)    Fe + H₂O → Fe₃O₄ ⁺ H₂
(vi)    H₂S + O₂ → H₂O + S
(vii)    H₂ + N₂ →NH₃.

Balance the following chemical equations:
(i)    NaOH + H₂SO₄ → Na₂SO₄ + H₂O
(ii)    HNO₃ + Ca(OH)₂ → Ca(N0₃)₂ + H₂ O
(iii)    FeCl₂ + H₂S → HCl + FeS 

What information is available from the following equation:
CaCO₃ + 2HCl→ CaCl₂ + H₂O+ CO₂

Write and balance the following equations presented to you as written statements:

(i) Magnesium carbonate plus hydrochloric acid produces magnesium chloride plus water plus carbon dioxide gas.
(ii)    Aluminium plus chlorine gas produces aluminium trichloride.
(iii)    Nitrogen plus hydrogen produces ammonia.
(iv)    Calcium plus sulphur produces calcium sulphide.
(v)    Magnesium burns in CO₂ to form magnesium oxide and carbon.