Explain the term - 'chemical reaction'.

State whether a physical or a chemical change is involved during - a chemical reaction - giving reasons.

The equation below represents - a chemical reaction

2KMnO₄ + 2H₂O + 5SO₂ → K₂SO₄ + 2MnSO₄ + 2H₂SO₄

1. In the above equation for the chemical reaction - is the equation balanced.
2. Name the products of the above reaction.
3. Give a reason why the reactants have formed - new products.
4. Give an equation for a chemical reaction involving -
   1. Two gases - as the reactants.
   2. A trivalent metal & a dilute acid - as the reactants.
   3. A divalent metal & a non-metal - as the reactants.

Give a balanced equation for each of the following:

1. A chemical reaction involving a change in colour - of the reactant to the residual product from -
   1. Blue to black
   2. Orange to green
   3. Light green to black
   4. White to yellow
2. A chemical reaction resulting in evolution of a gas which -
   1. Turns moist blue litmus faint red, lime water milky and has no effect on acidified KMnO4 soln.
   2. Turns moist red litmus blue & gives dense white fumes with a glass rod dipped in conc. HCI.
   3. Turns moist blue litmus red, lime water milky & acidified KMnO4 soln. from pink to clear colourless.
3. A chemical reaction resulting in formation of a precipitate
   1. Reddish brown in colour
   2. Pale blue in colour
   3. Dirty green in colour
   4. Gelateneous white in colour

The different types of chemical reactions maybe represented as -

1. A + B → AB
2. AB → A + B
3. A + BC → AC + B
4. A⁺ B^- + C⁺ D^- → A⁺ D^- + C⁺ B^-

1. Match the type of reactions given below with- i], ii], iii], iv]
   1. Double decomposition reaction
   2. Displacement reaction
   3. Direct combination reaction
   4. Decomposition reaction
2. Define the type of chemical reaction represented by iii].
3. To which type i.e. i], ii], iii] or iv] - does the reaction given below belong :

CI₂ + 2KBr → 2KCI + Br₂

4. In reaction i] - what do A & B represent on the left side.
5. In reaction iii] - what does 'B' represent on the right side.
6. State why reaction iv] - is represented as A⁺B^- + C⁺D^- and not as AB + CD.
7. State why reaction iv] - is represented as precipitation & neutralization. Differentiate between the two.