A 1000 g aqueous solution of CaCO₃ contains 10 g of calcium carbonate. The hardness of the solution is:

1. 10 ppm

2. 100 pm

3. 1000 ppm

4. 10000 ppm

Hydrogen adsorbed on palladium is known as:

1. Atomic H

2. Nascent H

3. Occluded H

4. Heavy H

A compound that acts as both reducing and oxidising agent is-

1. H₂SO₄

2. H₂O₂

3. KOH

4. KMnO₄

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

H₂O₂ is prepared in the laboratory by the reaction of :

1. MnO₂ with dilute cold H₂SO₄

2. BaO₂ and  CO₂ bubbling through cold water

3. PbO₂ with an acidified solution of KMnO₄

4. Na₂O₂ with boiling water

Temporary hardness is caused due to the presence of:

1. CaSO₄

2. CaCl₂

3. CaCO₃

4. Ca(HCO₃)₂

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