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

What is formed when calcium carbide reacts with heavy water?

1. C₂D₂

2. CaD₂

3. Ca₂D₂O

4. CD₂

Decomposition of H₂O₂ is accompanied by:

1. decrease in free energy

2. increase in free energy

3. no change in free energy

4. evolution of heat

Ionic hydrides react with water to give:

1. Acidic solutions.

2. Basic solutions.

3. Hydride ion.

4. Protons.

A neutral hydride among the following is -

1. H₂S

2. H₂O

3. H₂Se

4. H₂Te

Which is used to determine hardness of water volumetrically ?

1. H₂C₂O₄

2. Na₂S₂O₃

3.Sod. citrate

4. Di sodium salt of EDTA

The ratio of electron, proton and neutron in tritium is:

1. 1:1:1

2. 1:1:2

3. 2:1:1

4. 1:2:1

Both temporary and permanent hardness are removed on boiling water with:

1. Ca(OH)₂

2. Na₂CO₃

3. CaCO₃

4. CaO