P Block elements G15-18

Though Nitrogen exhibits +5 oxidation state, it does not form pentahalide. Give reason.

$PH_{3}$ has a lower boiling point than $NH_{3}$. Why?

Why are pentahalides more covalent than trihalides?

Why is $BiH_{3}$ the strongest reducing agent amongst all the hydrides of Group 15 elements?

Write the reaction of thermal decomposition of sodium azide.

Why is $N_{2}$ less reactive at room temperature?

Why does $NH_{3}$ act as a Lewis base?

Mention the conditions required to maximize the yield of ammonia.

How does ammonia react with a solution of $Cu^{2+}$?

Why does $NO_{2}$ dimerise?

What is the covalence of nitrogen in $N_{2}O_{5}$?

In what way can it be proved that $PH_{3}$ is basic in nature?

Bond angle in $PH_{4}^{+}$ is higher than that in $PH_{3}$. Why?

What happens when white phosphorus is heated with concentrated $NaOH$ in an inert atmosphere of $CO_{2}$?

Why does $PCl_{3}$ fume in moisture?

Are all the five bonds in $PCl_{5}$ molecule equivalent? Justify.

What happens when $PCl_{5}$ is heated?

Write a balanced equation for the hydrolytic reaction of $PCl_{5}$ in heavy water.

How do you account for the reducing behavior of $H_{3}PO_{2}$ on the basis of its structure?

What is the basicity of $H_{3}PO_{4}$?

Phosphorus in solid state is ionic, why?

Group 16 elements generally show lower first ionization enthalpy than Group 15 elements. Why?

$H_{2}S$ is less acidic than $H_{2}Te$. Why?

Write the order of thermal stability of the hydrides of Group 16 elements.

Why is $H_{2}O$ a liquid and $H_{2}S$ a gas?

Which of the following does not react with oxygen directly: Zn, Ti, Pt, Fe?

Why does $O_{3}$ act as a powerful oxidizing agent?

How is $O_{3}$ estimated quantitatively?

Which form of sulphur shows paramagnetic behavior?

What happens when $SO_{2}$ is passed through an aqueous solution of Fe(III) salt?

Are the two $S-O$ bonds in $SO_{2}$ molecule equal?

How is the presence of $SO_{2}$ detected?

Write the conditions to maximize the yield of $H_{2}SO_{4}$ by Contact process.

Why is $K_{a2} \ll K_{a1}$ for $H_{2}SO_{4}$ in water?

Halogens have maximum negative electron gain enthalpy in their periods. Why?

Although the electron gain enthalpy of $F$ is less negative than $Cl$, $F_{2}$ is a stronger oxidizing agent. Why?

Fluorine exhibits only -1 oxidation state whereas other halogens exhibit +1, +3, +5, +7. Explain.

Give two examples to show the anomalous behavior of fluorine.

Write the reaction of $Cl_{2}$ with hot and concentrated $NaOH$. Is it disproportionation?

When $HCl$ reacts with powdered iron, it forms $FeCl_{2}$ not $FeCl_{3}$. Why?

Deduce the molecular shape of $BrF_{3}$ on the basis of VSEPR theory.

Why is $ICl$ more reactive than$I_{2}$?

Why are the elements of Group 18 known as noble gases?

Noble gases have very low boiling points. Why?

Does the hydrolysis of $XeF_{6}$ lead to a redox reaction?

Why is helium used in diving apparatus?

Balance: $XeF_{6} + H_{2}O \rightarrow XeO_{2}F_{2} + HF$

Why has it been difficult to study the chemistry of radon?

Give the reason for bleaching action of $Cl_{2}$.

Why does $NH_{3}$ form hydrogen bonds but $PH_{3}$ does not?

The $H-N-H$ angle value is higher than $H-P-H$ angle. Why?

Why does $R_{3}P=O$ exist but $R_{3}N=O$ does not?

Explain why $NH_{3}$ is basic while $BiH_{3}$ is only feebly basic.

Nitrogen exists as diatomic molecule ($N_2$) and phosphorus as $P_{4}$. Why?

Give the disproportionation reaction of $H_{3}PO_{3}$.

Can $PCl_{5}$ act as an oxidizing as well as a reducing agent?

Why is dioxygen a gas but sulphur a solid?

How do you account for the formation of oxides having $O^{2-}$ despite high positive electron gain enthalpy for $O \rightarrow O^{2-}$?

Why are halogens colored?

What inspired N. Bartlett to react Xe with $PtF_{6}$?

Arrange in increasing bond dissociation enthalpy: $F_{2}, Cl_{2}, Br_{2}, I_{2}$.

Arrange in increasing acid strength: $HF, HCl, HBr, HI$.

Arrange in increasing base strength: $NH_{3}$ to $BiH_{3}$.

Structure of noble gas species isostructural with $ICl_{4}^{-}$.

Structure of noble gas species isostructural with $BrO_{3}^{-}$.

Why do noble gases have comparatively large atomic sizes?

Why is the $N-N$ bond weaker than the single $P-P$ bond?

Based on what property is white phosphorous used in Holmes signals?

$Al_{2}O_{3}$ is amphoteric. Show reactions.

During dilution, why must $H_{2}SO_{4}$ be added to water, not vice-versa?

Ionic character of metal halides decreases from $MF$ to $MI$. Give reason.

Ionic character of metal chlorides decreases as oxidation state increases. Explain.

What is the value of the bond enthalpy of the $N \equiv N$ bond, and what does it imply about the reactivity of dinitrogen at room temperature?

In the industrial preparation of $HNO_3$ (Ostwald’s process), what catalyst and temperature conditions are used for the oxidation of $NH_3$?

Write the formula and color of the complex formed in the 'Brown Ring Test' for nitrates.

What are the products when Zinc reacts with dilute nitric acid?

What are the products when Zinc reacts with concentrated nitric acid?

Why is White Phosphorus more reactive than Red Phosphorus in terms of bond angle strain?

What reaction is used to prepare $PCl_5$ from white phosphorus using a sulfur compound?

Describe the ionic structure of $PCl_5$ in the solid state.

Why is molecular oxygen ($O_2$) paramagnetic despite having an even number of electrons?

Why is a "silent electrical discharge" necessary for the preparation of ozone from oxygen?

How do nitrogen oxides emitted from supersonic jets affect the ozone layer? (Give the reaction).

At what temperature (transition temperature) does Rhombic sulphur transform into Monoclinic sulphur?

Which form of sulphur is paramagnetic and dominant at elevated temperatures (~1000 K)?

Identify the catalyst used in the contact process for the conversion of $SO_2$ to $SO_3$.

Write the chemical equation for the charring action of concentrated $H_2SO_4$ on sucrose (cane sugar).

What are the products obtained when Copper reacts with concentrated $H_2SO_4$?

What is the chemical formula of Oleum?

What is the product formed when $SO_2$ reacts with $Cl_2$ in the presence of charcoal?

Compare the reducing/oxidizing nature of $SO_2$ and $TeO_2$.

Why is $SF_6$ exceptionally stable towards hydrolysis and chemical attacks?

Compare the bond dissociation enthalpy of $F_2$ and $Cl_2$.

Write the chemical equation for the reaction of $F_2$ with water.

Write the chemical equation for the reaction of $Cl_2$ with water.

Name the catalyst and temperature used in Deacon's process for the manufacture of chlorine.

What are the products when $Cl_2$ reacts with cold and dilute$NaOH$?

What products are formed when excess ammonia reacts with chlorine?

What products are formed when ammonia reacts with excess chlorine?

What is the composition of Aqua Regia?

Write the chemical equation for the reaction of Gold ($Au$) with Aqua Regia.

What is the specific use of $I_2O_5$ in chemical estimation?

Write the composition of Bleaching Powder.

Why does $HF$ have a higher boiling point than $HCl$, $HBr$, and $HI$?

When an interhalogen compound $XX'$ undergoes hydrolysis, which halogen forms the hypohalite/halite/halate ion?

What is the molecular shape of $ClF_3$?

What is the molecular shape of $IF_7$?

Give one major industrial use of $ClO_2$.

What is the formula of the first noble gas compound prepared by Neil Bartlett?

What ratio of $Xe$ to $F_2$ is required to prepare $XeF_4$?

What ratio of $Xe$ to $F_2$ is required to prepare $XeF_2$?

What ratio of $Xe$ to $F_2$ is required to prepare $XeF_6$?

What are the products of the hydrolysis of $XeF_2$?

Write the equation for the hydrolysis of $XeF_4$.

What is the product of the partial hydrolysis of $XeF_6$ with one mole of water?

What is the product of the partial hydrolysis of $XeF_6$ with two moles of water?

What is the product of the complete hydrolysis of $XeF_6$?

Describe the structure and hybridization of $XeO_3$.

Describe the structure of $XeOF_4$.

What is the product formed when $XeF_2$reacts with a Lewis acid like$PF_5$?

Why is liquid Helium used in NMR spectrometers and MRI systems?

How is Radon ($Rn$) obtained?