$\mathrm{A}+{\mathrm{H}}_2\mathrm{O}\stackrel{}{\to }\mathrm{B}+\mathrm{HCl}$
$\mathrm{B}+{\mathrm{H}}_2\mathrm{O}\stackrel{}{\to }\mathrm{C}+\mathrm{HCl}$

Compound (A),(B) and (C) will be respectively :

(a) ${\mathrm{PCl}}_5, {\mathrm{POCl}}_3, {\mathrm{H}}_3{\mathrm{PO}}_3$                 (b) ${\mathrm{PCl}}_5, {\mathrm{POCl}}_3, {\mathrm{H}}_3{\mathrm{PO}}_4$

(c) ${\mathrm{SOCl}}_2, {\mathrm{POCl}}_3, {\mathrm{H}}_3{\mathrm{PO}}_3$               (d) ${\mathrm{PCl}}_3, {\mathrm{POCl}}_3, {\mathrm{H}}_3{\mathrm{PO}}_4$

Which of the following is in the correct sequence?

[For the correct order mark (T) and for the incorrect order mark (F)]:

In which of the following compounds hydrolysis takes place through ${\mathrm{S}}_{{\mathrm{N}}^1}$ and ${\mathrm{S}}_{{\mathrm{N}}^2}$ mechanism respectively?

(a) ${\mathrm{NF}}_3, {\mathrm{NCl}}_3$                       

(b) ${\mathrm{P}}_4{\mathrm{O}}_{10}, {\mathrm{SiCl}}_4$

(c) ${\mathrm{SF}}_4, {\mathrm{TeF}}_6$                       

(d) ${\mathrm{SiCl}}_4, {\mathrm{SiF}}_4$ 

Incorrect statement regarding PH₃ is:

1. It is produced by the hydrolysis of Ca₃P₂${\mathrm{}}_{}$

2. It gives a black ppt, Cu₃P₂ with a CuSO₄ solution.

3. It spontaneously burns in the presence of ${\mathrm{P}}_2{\mathrm{H}}_4$

4. It does not react with ${\mathrm{B}}_2{\mathrm{H}}_6$

The false statement regarding hydrides from the 15th group is:

A non-metal M forms ${\mathrm{MCl}}_3, {\mathrm{M}}_2{\mathrm{O}}_5 \mathrm{and} {\mathrm{Mg}}_3{\mathrm{M}}_2$ but does not form ${\mathrm{MI}}_5$. Then incorrect statement regarding non-metal M is:

(a) M can form multiple bond

(b) M is of second period element 

(c) Atomicity of non-metal is 4

(d) The range of oxidation number for M is +5 to -3

The correct order of $\mathrm{S}—\mathrm{S}$ bond length in the following oxyanion is :

(I) ${\mathrm{S}}_2{\mathrm{O}}_4^{2-}$                  (II) ${\mathrm{S}}_2{\mathrm{O}}_5^{2-}$                      (III) ${\mathrm{S}}_2{\mathrm{O}}_6^{2-}$

(a) I$>$II$>$III                                      (b) I$>$III$>$II

(c) III$>$II$>$I                                       (d) III$>$I$>$II

Consider the following statements in respect of oxides of sulphur.

(1) In gas phase ${\mathrm{SO}}_2$ molecule is V-shape.

(2) In gas phase ${\mathrm{SO}}_3$ molecule is planar.

(3) $\mathrm{y}‐{\mathrm{SO}}_3$ is cyclic trimer.

Which of the above statements are correct ?

(1) 1 and 2 only                             

(2) 2 and 3 only

(3) 1 and 3 only                             

(4) 1, 2 and 3

The gas that cannot be collected over water is:

1. ${\mathrm{N}}_2$                                   

2. ${\mathrm{O}}_2$

3. ${\mathrm{SO}}_2$                                 

4. ${\mathrm{PH}}_3$

One gas bleaches the colour of flowers by reduction, while the other gas bleaches by oxidation. The two gases, respectively, are:

1. $\mathrm{CO}$ $\mathrm{and}$ ${\mathrm{Cl}}_2$                             

2. ${\mathrm{H}}_2\mathrm{S}$ $\mathrm{and}$ ${\mathrm{Br}}_2$

3. ${\mathrm{NH}}_3$ $\mathrm{and}$ ${\mathrm{SO}}_3$                           

4. ${\mathrm{SO}}_2$ $\mathrm{and}$ ${\mathrm{Cl}}_2$