Which loses weight on exposure to the atmosphere ?

1. Concentrated H₂SO₄

2. Solid NaOH

3. A saturated solution of CO₂

4. Anhydrous sodium carbonate

The element among the following that does not show inert pair effect is-

An amphoteric  oxide among the following is-

1. CO₂

2. CO

3. SnO₂

4. CaO

In B₂H₆ 

(1) there is direct boron-boron bond

(2) the structure is similar to that of C₂H₆

(3) the boron atoms are linked through hydrogen bridges

(4) all the atoms are in one plane

From the B₂H₆ all the following can be prepared except:

(1) H₃BO₃

(2) [BH₂(NH₃)₂]+ [BH₄]-

(3) B₂(CH₃)₆

(4) NaBH₄

The correct order of ease of hydrolysis is :

1. CCl₄ < SiCl₄ < PCl₅ < AlCl₃

2. AlCl₃ < CCl₄ < PCl₅ < SiCl₄

3. CCl₄ < AlCl₃ < PCl₅ < SiCl₄

4. CCl₄ < AlCl₃ < SiCl₄ < PCl₅

The number of carbon atoms per unit cell of diamond unit cell is:-

1. 4

2. 8

3. 6

4. 1

${\mathrm{BX}}_3+{\mathrm{NH}}_3\stackrel{\mathrm{R}.\mathrm{T}.}{\to }{\mathrm{BX}}_3 .{\mathrm{NH}}_3+$ Heat of adduct formation $\left(∆\mathrm{H}\right)$

The numerical value of $∆\mathrm{H}$ is found to be maximum for :

(1) ${\mathrm{BF}}_3$                               

(2) ${\mathrm{BCl}}_3$

(3) ${\mathrm{BBr}}_3$                             

(4) ${\mathrm{BI}}_3$

Borax is converted into crystalline boron by the following steps:

          $\mathrm{Borax}\stackrel{\mathrm{X}}{\to }{\mathrm{H}}_3{\mathrm{BO}}_3\stackrel{∆}{\to }{\mathrm{B}}_2{\mathrm{O}}_3\underset{∆}{\overset{\mathrm{Y}}{\to }}\mathrm{B}$

X and Y are respectively :

1. HCl, Mg                                 
2. HCl, C
3. C, Al 
4. HCl, Al

The dissolution of $\mathrm{Al}(\mathrm{OH}{)}_3$ in a solution of $\mathrm{NaOH}$ results in the formation of -

1. ${\left[\mathrm{Al}{\left({\mathrm{H}}_2\mathrm{O}\right)}_4{\left(\mathrm{OH}\right)}_2\right]}^{+}$       

2. $\left[\mathrm{Al}{\left({\mathrm{H}}_2\mathrm{O}\right)}_3{\left(\mathrm{OH}\right)}_3\right]$

3. ${\left[\mathrm{Al}{\left({\mathrm{H}}_2\mathrm{O}\right)}_2{\left(\mathrm{OH}\right)}_4\right]}^{-}$     

4. $\left[\mathrm{Al}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6{\left(\mathrm{OH}\right)}_3\right]$