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

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

Incorrectly matched characteristic is:

1. S₈: covalent lattice

2. P₄: tetrahedron

3. S₅^2-: zigzag

4. SiO₂: Covalent lattice

Which of the following has been arranged in order of decreasing bond dissociation energy:

1. P-O>Cl-O>S-O

2. P-O>S-O>Cl-O

3. S-O>Cl-O>P-O

4. Cl-O>S-O>P-O

Compound among the following with an S-S bond is :

1. H₂S₂O₇

2. H₂SO₅

3. H₂S₂O₈

4. H₂S₂O₆

The bleaching action of SO₂ is due to its

1. Acidic property

2. Basic property

3. Reducing property

4. Oxidising property

The following solid exists in the form of ions:-

(1) BI₃

(2) BCl₃

(3) BF₃

(4) CaBO₂

The correct order of boiling points for group 16 hydrides is:

1. H₂O < H₂S < H₂Se < H₂Te

2. H₂Te < H₂Se < H₂S < H₂O

3. H₂S < H₂Se < H₂Te < H₂O

4. H₂O < H₂Te < H₂Se < H₂S

In which pair of ions both the species contain S-S bond?

$\left(\mathrm{a}\right) {\mathrm{S}}_2{\mathrm{O}}_7^{2-}, {\mathrm{S}}_2{\mathrm{O}}_3^{2-}$
$\left(\mathrm{b}\right) {\mathrm{S}}_4{\mathrm{O}}_6^{2-}, {\mathrm{S}}_2{\mathrm{O}}_3^{2-}$
$\left(\mathrm{c}\right) {\mathrm{S}}_2{\mathrm{O}}_7^{2-}, {\mathrm{S}}_2{\mathrm{O}}_8^{2-}$
$\left(\mathrm{d}\right) {\mathrm{S}}_4{\mathrm{O}}_6^{2-}, {\mathrm{S}}_2{\mathrm{O}}_7^{2-}$

Hot concentrated sulphuric acid is a moderately strong oxidising agent. Which of the following reaction doe not show oxidising behaviour?

(a) Cu + 2H₂SO₄ $\to$CuSO₄ + SO₂ + 2H₂O

(b) 3S + 2H₂SO₄ $\to$3SO₂ + 2H₂O

(c) C + 2H₂SO₄ $\to$CO₂ + 2SO₂ + 2H₂O

(d) CaF₂ + H₂SO₄ $\to$CaSO₄ + 2HF