Correlate the items listed in Column I with those listed in Column II. 

Codes

CO2  is used as a fire extinguisher because -

1. ${\mathrm{CO}}_2$ has high lattice energy.

2. ${\mathrm{CO}}_2$ will be effective in isolating the burning surface from dihydrogen and dioxygen.

3. ${\mathrm{CO}}_2$ is lighter than dioxygen.

4. ${\mathrm{CO}}_2$ is lighter than dihydrogen.

The correct statement about electron-deficient hydride is that it:

Ionic hydrides are formed by:

1. Transition metals.

2. Elements of very high electropositivity.

3. Elements of very low electropositivity.

4. Metalloids.

The group that has hydride formed by only one member is -

1.  6

2.  7

3.  8

4.  9

A neutral hydride among the following is -

1. H₂S

2. H₂O

3. H₂Se

4. H₂Te

 Covalent hydride among the following is -

1. ${\mathrm{NH}}_3$ $\mathrm{and}$ ${\mathrm{B}}_2{\mathrm{H}}_6$

2. ${\mathrm{CaH}}_2$ $\mathrm{and}$ ${\mathrm{B}}_2{\mathrm{H}}_6$

3. $\mathrm{NaH}$ $\mathrm{and}$ ${\mathrm{CaH}}_2$

4. $\mathrm{NaH}$ $\mathrm{and}$ ${\mathrm{NH}}_3$

Hydrogen combines directly with:

1. Ca

2. Cu

3. Zn

4. Fe

Atomic hydrogen or oxy-hydrogen torch is used for cutting and welding purposes because:

Ionic hydrides react with water to give:

1. Acidic solutions.

2. Basic solutions.

3. Hydride ion.

4. Protons.