Very pure hydrogen (99.9%) can be made by which of the following processes ?

1. Mixing natural hydrocarbons of high molecular weight

2. Electrolysis of water

3. Reaction of salt like hydrides with water

4. Reaction of methane with steam

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.

Hydrogen combines directly with:

1. Ca

2. Cu

3. Zn

4. Fe

Acidified solution of chromic acid on treatement with H₂O₂ yields :

1. ${\mathrm{CrO}}_3 + {\mathrm{H}}_2\mathrm{O} + {\mathrm{O}}_2$

2. ${\mathrm{Cr}}_2{\mathrm{O}}_2 + {\mathrm{H}}_2\mathrm{O} + {\mathrm{O}}_2$

3. ${\mathrm{CrO}}_5 + {\mathrm{H}}_2\mathrm{O} + {\mathrm{K}}_2{\mathrm{SO}}_4$

4. ${\mathrm{H}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7 + {\mathrm{H}}_2\mathrm{O} + {\mathrm{O}}_2$

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

On bubbling CO₂ through a solution of barium peroxide in water:

1. O₂ is formed

2. H₂CO₃ is formed

3. H₂O₂ is formed

4. H₂ is formed

A mixture of hydrazine and 60 to 90 percent of H₂O₂ solution is:

1. antiseptic

2. rocket fuel

3. germicide

4. insecticide

A given solution of H₂O₂ is 30 volume. Its concentration in terms of molarity is:

1. 9.1 M

2. 2.68 M

3. 2.5 M

4. 26.8 M

The decomposition of H₂O₂ is accelerated by:

1. traces of acids

2. finely divided metals

3. acetanilide

4. alcohol

 Hardness of water cannot be removed by -

1. Clark's method

2. Adding washing soda

3. Calgon process

4. Filtration