The lightest gas is :

1. nitrogen

2. helium

3. oxygen

4. hydrogen

The critical temperature of water is higher than that of O₂ because H₂O molecule has:

1. fewer electrons than oxygen

2. two covalent bonds

3. V-shape

4. dipole moment

Benzene is oxidized by H₂O₂ in presence of FeSO₄ to:

1. phenol

2. cyclohexane

3. benzaldehyde

4. benzoic acid

10 volumes of H₂O₂ has a strength of approximately:

1. 3%

2. 30%

3. 10%

4. 5%

Which is not true in case of H₂O₂?

1. It is more stable in basic solution

2. It acts as strong oxidising agent in acid and basic solutions

3. It is decomposed by MnO₂

4. It behaves as reducing agent towards KMnO₄

Decmposition of H₂O₂ is retarded by:

1. acetanilide

2. alcohol

3. H₃PO₄

4. all of these

Density of water is maximum at:

1. 0$°$C

2. 100 $°$C

3. 4$°$C

4. 0 K

Atomic hydrogen is obtained by:

1. electrolysis of heavy water

2. reaction of water with heavy metals

3. thermal decomposition of water

4. passing silent electric discharge through hydrogen at low pressure

Permutit is:

1. hydrated sodium aluminium silicate

2. sodium hexa meta-phosphate

3. sodium silicate

4. sodium meta-aluminate

Hydrogen is not obtained when zinc reacts with:

1. cold water

2. dil. H₂SO₄

3. dil HCl

4. hot 20% NaOH