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

1. Fe

2. Mg or Mn

3. Cu

. Al

The lightest gas is :

1. nitrogen

2. helium

3. oxygen

4. hydrogen

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

Hydrogen is not obtained when zinc reacts with:

1. cold water

2. dil. H₂SO₄

3. dil HCl

4. hot 20% NaOH

Para hydrogen at room temperature is:

1. Less stable than ortho hydrogen.

2. More stable than ortho hydrogen.

3. As stable as ortho hydrogen.

4. None of the above.

What is formed when calcium carbide reacts with heavy water?

1. C₂D₂

2. CaD₂

3. Ca₂D₂O

4. CD₂

 The formation of atomic hydrogen from molecular hydrogen will be favoured most at ?

1. High temperature and high pressure

2. Low temperature and low pressure

3. High temperature and low pressure

4. Low temperature and high pressure

The ortho and para hydrogen possess:

1. same physical properties but different chemical properties

2. different physical properties but same chemical properties

3. same chemical and physical properties

4. different physical and chemical properties

Hydrogen adsorbed on palladium is known as:

1. Atomic H

2. Nascent H

3. Occluded H

4. Heavy H

Poorest reducing agent among following is

1. atomic hydrogen

2. nascent hydrogen

3. dihydrogen

4. all have same reducing strength