Which one of the following has (have) octahedral geometry?

(i) SbCl${}_6^{-}$

(ii) SnCl${}_6^{2-}$

(iii) XeF₆

(iv) IO${}_6^{5-}$

• (i), (ii) and (iv)

• (ii), (iii) and (iv)

• (i), (ii) and (iii)

• All of these

Among the following compounds of boron, the species which also forms $\mathrm{\pi }$-bond in addition to σ-bonds is

• BH₃

• B₂H₆

• BF₃

• BF${}_4^{-}$

Which of the following statement is correct ?

• BCl₃ and AlCl₃ are both Lewis acids and AlCl₃ is stronger than BCl₃

• BCl₃ and AlCl₃ are both equally strong Lewis acid

• Both BCl₃ and AlCl₃ are not Lewis acid

• BCl₃ and AlCl₃ are both Lewis acids and BCl₃ is stronger than AlCl₃

The paramagnetic species is

• SiO₂

• TiO₂

• BaO₂

• KO₂

In view of ${∆}_{\mathrm{r}}\mathrm{G}°$ for the following reactions

PbO₂ + Pb → 2PbO, ${∆}_{\mathrm{r}}\mathrm{G}°\mathrm{r}$

SnO₂ + Sn → 2SnO, ${∆}_{\mathrm{r}}\mathrm{G}°\mathrm{r}$

Which oxidation state is more characteristic for lead and tin?

• For lead +2, for tin +2

• For lead +4, for tin +4

• For lead +2, for tin +4

• For lead +4, for tin +2

In terms of polar character which one of the following orders is correct?

• H₂S < NH₃ < H₂O < HF

• H₂O < NH₃ < H₂S < HF

• HF < H₂O < NH₃ < H₂S

• NH₃ < H₂O < HF < H₂S

Identify the Bronsted acid in the following equation

${\mathrm{PO}}_4^{3-} + {\mathrm{H}}_2\mathrm{O}\hspace{0.17em}\left(\mathrm{l}\right) \to {\mathrm{HPO}}_4^{2-} \left(\mathrm{aq}\right) + {\mathrm{OH}}^{-} \left(\mathrm{aq}\right)$

• PO${}_4^{3-}$

• HPO₄

• H₂O

• OH^-

The number of grams/ weight of NH₄Cl required to be added to 3 litres of 0.01 M NH₃ to prepare the buffer of pH = 9.45 at temperature 298 K (K_b for NH₃ is 1.85 × 10^-5)

• 0.354 gm

• 4.55 gm

• 0.455 gm

• 3.55 gm

For the reaction, 2HI (g) $\rightleftharpoons$H₂ (g) + I₂ (g) the degree of dissociation (α) of HI (g) is related to equilibrium constant K_p by the expression

• $\sqrt{\frac{1 + 2{\mathrm{K}}_{\mathrm{p}}}{2}}$

• $\sqrt{\frac{2{\mathrm{K}}_{\mathrm{p}}}{1+ 2{\mathrm{K}}_{\mathrm{p}}}}$

• $\frac{2\sqrt{{\mathrm{K}}_{\mathrm{p}}}}{1 + 2\sqrt{{\mathrm{K}}_{\mathrm{p}}}}$

• $\frac{1 + 2\sqrt{{\mathrm{K}}_{\mathrm{p}}}}{2}$

A 6% solution of sucrose C₂₂H₂₂O₁₁ is isotonic with 3% solution of an unknown organic substance. The molecular weight of unknown organic substance will be

• 684

• 171

• 100

• 342