Hydrogen is evolved by the action of cold dilute HNO₃ on:

1. Fe

2. Mg or Mn

3. Cu

. Al

A molten ionic hydride on electrolysis gives:

1. H⁺ ion moving towards the cathode.

2. H⁺ ion moving towards the anode.

3. H₂ is liberated at anode.

4. H₂ is liberated at cathode.

In solid hydrogen, the intermolecular bonding is:

1. ionic

2. van der Waals'

3. metallic

4. covalent

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