Why is CO₂ more effective than N₂ in extinguishing fires?

1. It is non-combustible.

2. It forms non-combustible products with burning substances.

3. It has a higher density than nitrogen.

4. It is chemically more reactive than nitrogen.

When sodium or potassium oxide is heated in a current of $C{O}_2<mspace\; width="1em"></mspace>at<mspace\; width="1em"></mspace>360°C$, we get:

1. sodium formate

2. sodium oxalate

3. sodium acetate

4. sodium carbonate

Which can be directly brought into gaseous state from solid state?

(1) CO

(2) Solid $C{O}_2$

(3) $P{H}_3$

(4) $CO+H_2$

Which is amphoteric oxide?

1. ZnO

2. MnO^-₄

3. CO₂

4. SiO

Which is a true acid anhydride?

(1) $A{l}_2{O}_3$

(2) CO

(3) CaO

(4) $C{O}_2$

$$Which of the following best explains the difference in hydrolytic behaviour between CCl₄ and SiCl₄?

1.  Carbon cannot expand its octet but silicon can expand.

2. The electronegativity of carbon is higher than that of silicon

3. The ionization potential of carbon is higher than that of silicon

4.  Carbon forms double and triple bonds, but silicon does not

Which is formed when $SiC{l}_4$ vapours are passed over hot Mg?

(1) $SiC{l}_2+MgC{l}_2$

(2) $Si+MgC{l}_2$

(3) $M{g}_{2}Si+C{l}_2$

(4) $MgSiC{l}_6$

Asbestors is chemically:

1. silicate of calcium and magnesium

2. calcium alumino silicate

3. magnesium alumino silicates

4. calcium silicate + calcium aluminates

Aqueous solution of sodium silicate is:

(1) acidic

(2) alkaline

(3) neutral

(4) insoluble

Quartz is made of silicon and oxygen joined in a network arrangement that is similar to:

1. Diamond

2. Graphite

3. $O_2$

4. None of the above