Fill in the blanks:

(a) A reaction in which two or more substances combine to form a single substance is called a …………… reaction.

(b) A …………… is a substance which changes the rate of a chemical reaction without undergoing a chemical change itself.

(c) The formation of gas bubbles in a liquid during a reaction is called …………… .

(d) The reaction between an acid and a base is called …………… .

(e) Soluble bases are called …………… .

(f) The chemical change involving iron and hydrochloric acid illustrates a …………… reaction.

(g) In the type of reaction called …………… two compounds exchange their positive an negative radicals respectively.

(h) A catalyst either …………… or …………… the rate of a chemical change but itself remains …………… at the end of the reaction.

(i) The chemical reaction between hydrogen and chlorine is a …………… reaction.

(j) When a piece of copper is added to silver nitrate solution, it turns …………… in colour.

Classify the following reactions as combination, decomposition, displacement, precipitation and neutralization. Also balance the equations.

(a) CaCO₃ (s) $\xrightarrow{\enspace\Delta\enspace}$ CaO (s) + CO₂ (g)

(b) Zn(s) + H₂SO₄ ⟶ ZnSO₄ (s) + H₂ (g)

(c) AgNO₃ (aq) + NaCl (aq) ⟶ AgCl(s) + NaNO₃

(d) NH₃ (g) + HCl (g) ⟶ NH₄Cl (s)

(e) CuSO₄ (aq) + H₂S (g) ⟶ CuS (s) + H₂SO₄ (l)

(f) Zn (s) + CuSO₄ (aq) ⟶ ZnSO₄ (aq) + Cu(s)

(g) Ca(s) + O₂ (g) ⟶ CaO(s)

(h) NaOH + HCl ⟶ NaCl + H₂O

(i) KOH + H₂SO₄ ⟶ K₂SO₄ + H₂O

Explain the following types of chemical reactions giving two examples for each of them:

(a) combination reaction

(b) decomposition reaction

(c) displacement reaction

(d) double displacement reaction

Write the missing reactants and products and balance the equations:

(a) NaOH + …………… ⟶ NaCl + …………….

(b) KClO₃ $\xrightarrow{\text{heat}}$ …………….. + ……………….

(c) …………. + HCl ⟶ NaCl + H₂O + ……………..