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

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. ${\mathrm{pH}}_1 > {\mathrm{pH}}_2 > {\mathrm{pH}}_{3 }> {\mathrm{pH}}_4$

Which of the following on heating produces NO₂?

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.

Concentrated nitric acid reacts with iodine to give:

1. HOI

2. HI

3. HIO₃

4. HIO4

Partial Hydrolysis of one mole of peroxodi-sulphuric acid produces:

1. two moles of sulphuric acid

2. two moles of peroxomono-sulphuric acid

3. one mole of sulphuric acid, one mole of peroxomono-sulphuric acid

4. one mole of sulphuric acid, one mole of peroxomono-sulphuric acid and one mole of hydrogen peroxide

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 compounds, which on heating do not produce N₂?

1. (NH₄)₂Cr₂O₇

2. NH₄Cl+NaNO₂

3. NH₄Cl+CaO

4. Ba(N₃)₂

Which of the following oxyacid contains both P-H and P-P bond simultaneously?

1. H₄P₂O₅

2. H₄P₂O₇

3. H₄P₂O₆

4. None

In which process does the nitrogen undergo oxidation?

1. N_{2 ^$\to$}2NH₃

2. N₂O_{4  ^$\to$}2NO₂

3. NO3^- _$\to$ N₂O₅

4. NO₂^{-  _$\to$}NO₃^-