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

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

When H₂O₂ is added to acidic ferrous sulphate solution:

1. electrons are gained by Fe²⁺

2. electrons are lost by Fe²⁺

3. there is no loss or gain of electrons

4. iron hydroxide precipitates

Which of the following pairs will not produce dihydrogen gas ?

1. Cu + HCl (dil.)

2. Fe + H₂SO₄

3. Mg + steam

4. Na + alcohol