Which of the following compounds has the lowest melting point?

1.  ${\mathrm{CaBr}}_2$

2.  ${\mathrm{Cal}}_2$

3.  ${\mathrm{CaF}}_2$

4.  ${\mathrm{CaCl}}_2$

Oxidation states of P in H₄P₂O₅, H₄P₂O₆, H₄P₂O₇, are respectively:

Among the following which is the strongest oxidising agent?

1. $F_2$

2. $B{r}_2$

3. $l_2$

4. $C{l}_2$

The electronegativity difference between N and F is greater than that between N and H yet the dipole moment of NH₃ (1.5 D) is larger than that of NF₃ (0.2 D). This is because:

The number of unpaired electrons in a paramagnetic diatomic molecule of an element with atomic number 16 is:

1. 2

2. 3

3. 4

4. 1

Sulphur trioxide can be obtained by which of the following reaction:

1. $CaS{O}_4+C\stackrel{∆}{\to }$

2. $F{e}_2(S{O}_4{)}_3\stackrel{∆}{\to }$

3. $S+H_{2}S{O}_4\stackrel{∆}{\to }$

4. $H_{2}S{O}_4+PC{l}_5\stackrel{∆}{\to }$

The incorrect statement regarding oxoacids of phosphorus is:

Which of the following compounds does not release oxygen when heated?

1. Zn(ClO₃)₂
2. K₂Cr₂O₇
3. (NH₄)₂Cr₂O₇
4. KClO₃

The acidity of diprotic acids in aqueous solution increases in the order:

1. H₂S < H₂Se < H₂Te

2. H₂Se < H₂S < H₂Te

3. H₂Te < H₂S < H₂Se

4. H₂Se < H₂Te < H₂S