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When a mixture of diborane and ammonia is heated, the final product is
1.  ${\mathrm{BH}}_3$
2.  ${\mathrm{NH}}_4{\mathrm{BH}}_4$
3.  ${\mathrm{NH}}_2{\mathrm{NH}}_2$
4.  ${\mathrm{B}}_3{\mathrm{N}}_3{\mathrm{H}}_6$

In the structure of borax, the numbers of boron atoms and B-O-B units, respectively, are
1.  4 and 5
2.  4 and 3
3.  5 and 4
4.  5 and 3

Which element does not form alum?
1.  Fe
2.  Li
3.  K
4.  Al

A species among the following that decomposes easily is: -

Lead pipes are corroded by:
(1) $H_{2}S{O}_4$
(2) HCl
(3) $C{H}_{3}COOH$
(4) Pure water

The amphoteric oxide among the following is -

The carbon of microphones used in public address systems is:
1.  graphite
2.  charcoal
3.  coke
4.  lamp black

Inorganic benzene is:
1. $\mathrm{BN}$
2. ${\mathrm{BF}}_4$
3. ${\mathrm{B}}_2{\mathrm{H}}_6$
4. ${\mathrm{B}}_3{\mathrm{N}}_3{\mathrm{H}}_6$

Which one of the following anions is present in chain structure silicates?
(a) ${\mathrm{Si}}_2{\mathrm{O}}_7^{6-}$                 (b) $({\mathrm{Si}}_2{\mathrm{O}}_5^{2-}{)}_{\mathrm{n}}$
(c) $({\mathrm{Si}}_2{\mathrm{O}}_6^{4-}{)}_{\mathrm{n}}$               (d) ${\mathrm{SiO}}_4^{4-}$

Which loses weight on exposure to the atmosphere ?
1. Concentrated H₂SO₄
2. Solid NaOH
3. A saturated solution of CO₂
4. Anhydrous sodium carbonate

Silicon carbide is used as:

The thermal stability order for group 14 halides is:
1.  ${\mathrm{GeX}}_2 < {\mathrm{SiX}}_2 < {\mathrm{SnX}}_2 < {\mathrm{PbX}}_2$
2.  ${\mathrm{SiX}}_2 < {\mathrm{GeX}}_2 < {\mathrm{PbX}}_2 < {\mathrm{SnX}}_2$
3.  ${\mathrm{SiX}}_2 < {\mathrm{GeX}}_2 < {\mathrm{SnX}}_2 < {\mathrm{PbX}}_2$
4.  ${\mathrm{PbX}}_2 < {\mathrm{SnX}}_2 < {\mathrm{GeX}}_2 < {\mathrm{SiX}}_2$

If a person is injured by the shot of a gun and all the pellets could not be removed, it may cause poisoning by:
1.  Hg
2.  Pb
3.  Fe
4.  As

On the addition of mineral acid to an aqueous solution of borax, the compound formed is:
1. borodihydride
2. orthoboric acid
3. metaboric acid
4. pyroboric acid