Calculate $∆$H in kJ for the following reaction:

C (g) + O₂ (g) → CO₂ (g)

Given that, 

H₂O (g) + C (g) → CO (g) + H₂ (g) ; $∆$H = +131 kJ

CO (g) + $\frac{1}{2}$O₂ (g) → CO₂ (g); $∆$H = -282 kJ

H₂ (g) + $\frac{1}{2}$O₂ (g) → H₂O (g); $∆$H = -242 kJ

• -393

• +393

• +655

• -655

12.

Boron halides behave as Lewis acids because of their  .......... nature.

• proton donor

• covalent

• electron deficient

• ionising

The correct order of reducing abilities of hydrides of V group elements is

• NH₃ < PH₃ < AsH₃ < SbH₃ < BiH₃

• NH₃ > PH₃ > AsH₃ > SbH₃ > BiH₃

• NH₃ < PH₃ > AsH₃ > SbH₃ > BiH₃

• SbH₃ > BiH₃ > AsH₃ > NH₃ > PH₃

The number of sigma and pi bonds in peroxodisulphuric acid are, respectively

• 9 and 4

• 11 and 4

• 4 and 8

• 4 and 9

The compound in which the number of d$\mathrm{\pi }$-p$\mathrm{\pi }$ bonds are equal to those present in ClO${}_4^{-}$

• XeF₄

• XeO₃

• XeO₄

• XeF₆

Which one of the following reactions represents the oxidising property of H₂O₂?

• 2KMnO₄ + 3H₂SO₄ + 5H₂O₂ → K₂SO₄ + 2MnSO₄ + 8H₂O + 5O₂

• 2K₃[Fe(CN)₆] + 2KOH + H₂O₂ → 2K₄[Fe(CN)₆] + 2H₂O + O₂

• PbO₂ + H₂O₂ → PbO + H₂O + O₂

• 2KI + H₂SO₄ + H₂O₂ → K₂SO₄ + I₂ + 2H₂O

Which of the following statements are correct for alkali metal compounds ?

(i) Superoxides are paramagnetic in nature.

(ii) The basic strengths of hydroxides increases down the group.

(iii) The conductivity of chlorides in their aqueous solutions decreases down the group.

(iv) The basic nature of carbonates in aqueous solutions is due to cationic hydrolysis.

• (i), (ii) and (iii) only

• (i) and (ii) only

• (ii), (iii) and (iv) only

• (iii) and (iv) only

Identify B in the following reaction

H₄SiO₄ $\underset{-{\mathrm{H}}_2\mathrm{O}}{\overset{1000°\mathrm{C}}{\to }}$ A $\underset{∆}{\overset{\mathrm{Carbon}}{\to }}$ B + CO

• corundum

• quartz

• silica

• carborundum

[Co(NH₃)₅SO₄]Br and [Co(NH₃)₅Br]SO₄ are a pair of ....... isomers.

• ionisation

• ligand

• coordination

• hydrate

Among the following compounds, which one is not responsible for depletion of ozone layer?

• CH₄

• CFCl₃

• NO

• Cl₂