Select the correct answer from A, B, C, D and E for each statement given below:

A: Hydrogen

B: Copper [II] oxide

C: Oxygen

D: Copper [II] hydroxide

E: Ammonia

1. The black residue obtained on heating copper carbonate.

2. The basic gas obtained when two gases react in presence of a catalyst and the reaction is exothermic.

3. The gas obtained when potassium chlorate is heated in the presence of a catalyst.

4. The pale blue precipitate obtained when copper [II] sulphate reacts with sodium hydroxide.

5. The gas which reacts with oxygen to give a neutral liquid.

Give a word equation for each of the following reactions.

1. Two solids which combine on heating, to give a liquid.

2. Two gasses which combine to give a solid.

3. A compound which on heating shows – color change from brown to yellow.

4. A salt which reacts with ammonium hydroxide to give a reddish-brown precipitate.

5. An exothermic reaction where both the reactants are gases, one of which is oxygen.

Name the following:

1. The silvery residue obtained on heating mercury [II] oxide.

2. The gas evolved when dilute acid is added to chalk [limestone].

3. Two non-metal which react explosively when brought in close contact.

4. Two gases which react under pressure in presence of a catalyst at elevated temperatures to give a gaseous product.

5. A catalyst which increases the rate of a chemical reaction.

Write word equations for the following chemical reactions given below. Also state the observation seen in each case.

1. ZnCO₃ $\xrightarrow{\Delta}$ ZnO + CO₂

2. NaCl + AgNO₃ ⟶ AgCl ↓ + NaNO₃

3. Na₂SO₃ + 2HCl $\xrightarrow{\Delta}$ 2NaCl + H₂O + SO₂

4. $2\text{SO}$2 + \text{O}2 \xrightleftharpoons [450\text{\degree C }]{\text{V}2\text{O}5} 2\text{SO}_3

5. Pb(NO₃)₂ + 2NH₄OH ⟶ 2NH₄NO₃ + Pb(OH)₂ ↓