The correct relationship between the pH of isomolar solutions of sodium oxide(pH₁), sodium sulphide (pH₂), sodium selenide (pH₃) and sodium telluride (pH₄) is -

1. ${\mathrm{pH}}_1$ $>$ ${\mathrm{pH}}_2$ $\approx$ ${\mathrm{pH}}_3$ $>$ ${\mathrm{pH}}_4$

2. ${\mathrm{pH}}_1$ $<$ ${\mathrm{pH}}_2$ $<$ ${\mathrm{pH}}_3$ $<$ ${\mathrm{pH}}_4$

3. ${\mathrm{pH}}_1$ $<$ ${\mathrm{pH}}_2$ $<$ ${\mathrm{pH}}_3$ $\approx$ ${\mathrm{pH}}_4$

4. ${\mathrm{pH}}_1$ $>$ ${\mathrm{pH}}_2$ $>$ ${\mathrm{pH}}_3$ $>$ ${\mathrm{pH}}_4$

By heating which of the following, would NO₂ be produced?

1. NaNO₃

2. AgNO₃

3. NH₄NO₃

4. NH₄NO₂

The formation of ${\mathrm{PH}}_4^{+}$ is difficult as compared to ${\mathrm{NH}}_4^{+}$ because

1. Lone pair of phosphorous is optically inert.

2. Lone pair of phosphorous resides in almost pure p - orbital.

3. Lone pair of phosphorous resides at sp³ orbital.

4. Lone pair of phosphorous resides in almost pure s - orbital.

Iodine on reaction with concentrated nitric acid forms:

1. HOI

2. HI

3. HIO₃

4. HIO₄

The partial hydrolysis of one mole of peroxodi-sulphuric acid produces  

Which of the following is the correct statement?

1. F₂ has higher dissociation energy than Cl₂

2. F has higher electron affinity than Cl

3. HF is stronger acid than HCl

4. Boiling point increases down the group in halogens

Incorrectly matched characteristic is:

1. S₈: covalent lattice

2. P₄: tetrahedron

3. S₅^2-: zigzag

4. SiO₂: Covalent lattice

Among the following reactions,  N₂ is not generated by heating:

1. (NH₄)₂Cr₂O₇

2. NH₄Cl + NaNO₂

3. NH₄Cl + CaO

4. Ba(N₃)₂

 An oxyacid among the following that contains both P-H and P-P bonds simultaneously is:

1. H₄P₂O₅

2. H₄P₂O₇

3. H₄P₂O₆

4. None of the above

Which of the following reactions indicate oxidation of nitrogen?

1. N₂  → 2NH₃

2. N₂O₄  → 2NO₂

3. NO3^- →  N₂O₅

4. NO₂^- → NO₃^-