Important Compounds of Group 15 Elements

State which of the following statements are true:

(i) Nitrogen is more reactive than phosphorus  $\left({\mathrm{P}}_4\right)$

(ii) All the bonds in  ${\mathrm{PCl}}_5$  are of equal length.

Nitrogen is known to form a variety of oxides and oxyacids. $\mathrm{NO}$ and ${\mathrm{N}}_2\mathrm{O}$ are unstable, while ${\mathrm{NO}}_2$ is a stable oxide. ${\mathrm{NO}}_2$ is a brown acidic gas at room temperature and on cooling below $20°\mathrm{C}$ gives ${\mathrm{N}}_2{\mathrm{O}}_4. {\mathrm{NO}}_2/{\mathrm{N}}_2{\mathrm{O}}_4$dissolves in water to give nitric acid. ${\mathrm{N}}_2{\mathrm{O}}_4$ reacts with $\mathrm{NO}$ to form ${\mathrm{N}}_2{\mathrm{O}}_3$. When some metals react with dil. ${\mathrm{HNO}}_3$ at room temperature, oxides of nitrogen in lower oxidation states are formed. The correct statement is

Explain the reason for non-reactivity of some metals with concentrated ${\mathrm{HNO}}_3$.

Phosphorous forms different oxyacids such as, hypophosphorous acid $\left({\mathrm{H}}_3{\mathrm{PO}}_2\right)$, orthophosphorous acid $\left({\mathrm{H}}_3{\mathrm{PO}}_3\right)$ and orthophosphoric acid $\left({\mathrm{H}}_3{\mathrm{PO}}_4\right)$. Orthophosphorous acid on heating forms orthophosphoric acid, which on heating first forms pyrophosphoric acid $\left({\mathrm{H}}_4{\mathrm{P}}_2{\mathrm{O}}_7\right)$ and on further heating forms polyphosphoric acid. The correct statement is.

In ${\mathrm{H}}_3{\mathrm{PO}}_2$ and ${\mathrm{H}}_3{\mathrm{PO}}_3$, the numbers of $\mathrm{P}-\mathrm{H}$ bonds are, respectively,

In which of the following cases the same gas will be obtained as the gas liberated on heating of ammonium dichromate?

The number of oxygen atoms attached to each $\mathrm{P}$ in ${\mathrm{P}}_2{\mathrm{O}}_5$ is

Give the names of metals that do not react with conc. ${\mathrm{HNO}}_3$.

In brown ring test for nitrate ions, brown ring is formed having composition 

When bismuth chloride is dissolved in water a white precipitate appears. The white precipitate is

Who has the highest bond angle among the hydrides of the15th group?

The colour of ${\mathrm{PCl}}_5$ powder is:

Phosphorus reacts with chlorine gas to give a colourless liquid, which fumes in moist air to produce $\mathrm{HCl}$ and

$\mathrm{N}-\mathrm{N}$ bond length minimum in :

What is the colour of phosphorus pentachloride.

A colourless, neutral, paramagnetic oxide of Nitrogen $\text{'}\mathrm{P}\text{'}$ on oxidation gives reddish brown gas $\mathrm{Q}.$ $\mathrm{Q}$ on cooling gives colourless gas $\mathrm{R}. \mathrm{R}$ on reaction with $\mathrm{P}$ gives blue solid $\mathrm{S}.$ Identify $\mathrm{P}, \mathrm{Q}, \mathrm{R}, \mathrm{S}$ respectively.

Which of the following compound on heating gives ${\mathrm{N}}_2\mathrm{O}?$

Which of the following is a mixed anhydride :

Concentrated nitric acid turns the colour of the skin into-

The compound produces ammonia when reacted with water is-