The given sequence among the following arrangements that is not strictly according to the property indicated against it.  

1.	H2O < H2S < H2Se < H2Te : \(\small{i n c r e a sin g \  p K_{a}\   v a l u e s}\)
2.	\(\small{N H_{3} <   P H_{3} <  A s H_{3} <  S b H_{3} :   i n c r e a sin g  \ a c i d i c  \ c h a r a c t e r}\)
3.	\(\small{C O_{} <  S i O_{} <  S n O_{}   <  P b O_{2} :  i n c r e a sin g \  o x i d i sin g  \ p o w e r} \)
4.	\(\small{H F  <  H C l   <  H B r  <  H I :  i n c r e a sin g \  a c i d i c  \ s t r e n g t h} \)

Total number of  bridging oxygen atoms present in $P_4{O}_{10}$ are:

1. 4

2. 2

3. 5

4. 6

Match List-I (substances) with List-II (processes) employed in the manufacture of the substances and select the correct option.

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

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:

Among the following which is the strongest oxidising agent?

1. $F_2$

2. $B{r}_2$

3. $l_2$

4. $C{l}_2$

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

Which of the following compounds has the lowest melting point?

1.  ${\mathrm{CaBr}}_2$

2.  ${\mathrm{Cal}}_2$

3.  ${\mathrm{CaF}}_2$

4.  ${\mathrm{CaCl}}_2$

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: