CrO₄^2- (yellow) changes to Cr₂O₇^2- (orange) in pH = x and vice versa in pH = y.

The value of x and y will be:

1. 6, and 8

2. 6, and 5

3. 8, and 6

4. 7, and 7

 Hardness of water cannot be removed by -

1. Clark's method

2. Adding washing soda

3. Calgon process

4. Filtration

The decomposition of H₂O₂ is accelerated by:

1. traces of acids

2. finely divided metals

3. acetanilide

4. alcohol

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

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

1. antiseptic

2. rocket fuel

3. germicide

4. insecticide

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

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

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

Hydrogen combines directly with:

1. Ca

2. Cu

3. Zn

4. Fe

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.