Conversion of Ethanol to Ethene by the action of concentrated sulphuric acid involves:

1. Dehydration
2. Dehydrogenation
3. Dehydrohalogenation
4. Hydrolysis

The oxidizing agent in the equation S + 2H₂SO₄ ⟶ 3SO₂ + 2H₂O is:

1. Sulphur
2. Sulphuric acid
3. Sulphur dioxide
4. Water

The compound that is not a constituent of the electrolytic mixture used in the Hall-Heroult's process is:

1. Al₂O₃
2. NaAlO₂
3. Na₃AlF₆
4. CaF₂

On passing ammonia gas over heated copper oxide for some time, a reddish-brown residue is left behind. What property of ammonia is demonstrated here?

1. Basic property
2. Oxidising property
3. Reducing property
4. Acidic property