Group 15 - dinitrogen, ammonia, nitrogen oxides, nitric acid and phosphorus — practice questions

Question 1 · difficulty L2 · understanding

The ratio of sigma and $$\pi$$ bonds present in pyrophosphoric acid is ___________.

Question 2 · difficulty L2 · understanding

Consider the following reactions: PCl 3 + H 2 O $$\to$$ A + HCl A + H 2 O $$\to$$ B + HCl The number of ionisable protons present in the product B is _______________.

Question 3 · difficulty L2 · understanding

Treatment of a gas ' $X$ ' with a freshly prepared ferrous sulphate solution gives a compound ' $Y$ ' as a brown ring. The compounds X and Y are.

• A. $$\mathrm{NO} \text { and }[\mathrm{Fe}(\mathrm{NO})] \mathrm{SO}_4$$
• B. $\mathrm{NO}_2$ and $\left[\mathrm{Fe}\left(\mathrm{NO}_2\right)\right] \mathrm{SO}_4$
• C. $\mathrm{N}_2 \mathrm{O}$ and $\left[\mathrm{Fe}\left(\mathrm{N}_2 \mathrm{O}\right)\right] \mathrm{SO}_4$
• D. $\mathrm{N}_2 \mathrm{O}_4$ and $\left[\mathrm{Fe}\left(\mathrm{N}_2 \mathrm{O}_4\right)\right] \mathrm{SO}_4$

Question 4 · difficulty L2 · understanding

Regarding the hydrides of group 15 elements $\mathrm{EH}_3(\mathrm{E}=\mathrm{N}, \mathrm{P}, \mathrm{As}, \mathrm{Sb})$, select the correct statement from the following : A. The stability of hydrides decreases down the group. B. The basicity of hydrides decreases down the group. C. The reducing character increases down the group. D. The boiling point increases down the group. Choose the correct answer from the options given below :

• A. A, B & C only
• B. A, B, C& D
• C. A & D only
• D. B & C only

Question 5 · difficulty L2 · understanding

In qualitative test for identification of presence of phosphorous, the compound is heated with an oxidising agent. Which is further treated with nitric acid and ammonium molybdate respectively. The yellow coloured precipitate obtained is :

• A. $$\mathrm{Na}_3 \mathrm{PO}_4 \cdot 12 \mathrm{MoO}_3$$
• B. $$\left(\mathrm{NH}_4\right)_3 \mathrm{PO}_4 \cdot 12\left(\mathrm{NH}_4\right)_2 \mathrm{MoO}_4$$
• C. $$\mathrm{MoPO}_4 \cdot 21 \mathrm{NH}_4 \mathrm{NO}_3$$
• D. $$\left(\mathrm{NH}_4\right)_3 \mathrm{PO}_4 \cdot 12 \mathrm{MoO}_3$$

Question 6 · difficulty L2 · understanding

On passing a gas, '$$\mathrm{X}$$', through Nessler's regent, a brown precipitate is obtained. The gas '$$\mathrm{X}$$' is

• A. $$\mathrm{Cl}_2$$
• B. $$\mathrm{CO}_2$$
• C. $$\mathrm{NH}_3$$
• D. $$\mathrm{H}_2 \mathrm{S}$$

Question 7 · difficulty L2 · understanding

One mole of $$\mathrm{P}_{4}$$ reacts with 8 moles of $$\mathrm{SOCl}_{2}$$ to give 4 moles of $$\mathrm{A}, x$$ mole of $$\mathrm{SO}_{2}$$ and 2 moles of $$\mathrm{B} . \mathrm{A}, \mathrm{B}$$ and $$x$$ respectively are :

• A. $$\mathrm{POCl}_{3}, \mathrm{~S}_{2} \mathrm{Cl}_{2}$$ and 4
• B. $$\mathrm{PCl}_{3}, \mathrm{~S}_{2} \mathrm{Cl}_{2}$$ and 4
• C. $$\mathrm{POCl}_{3}, \mathrm{~S}_{2} \mathrm{Cl}_{2}$$ and 2
• D. $$\mathrm{PCl}_{3}, \mathrm{~S}_{2} \mathrm{Cl}_{2}$$ and 2

Question 8 · difficulty L2 · understanding

Dinitrogen is a robust compound, but reacts at high altitudes to form oxides. The oxide of nitrogen that can damage plant leaves and retard photosynthesis is :

• A. $$\mathrm{NO}$$
• B. $$\mathrm{NO}_{3}^{-}$$
• C. $$\mathrm{NO}_{2}$$
• D. $$\mathrm{NO}_{2}^{-}$$

Question 9 · difficulty L2 · understanding

White phosphorus reacts with thionyl chloride to give :

• A. $$\mathrm{PCl}_{5}, \mathrm{SO}_{2}$$ and $$\mathrm{S}_{2} \mathrm{Cl}_{2}$$
• B. $$\mathrm{PCl}_{3}, \mathrm{SO}_{2}$$ and $$\mathrm{S}_{2} \mathrm{Cl}_{2}$$
• C. $$\mathrm{PCl}_{3}, \mathrm{SO}_{2}$$ and $$\mathrm{Cl}_{2}$$
• D. $$\mathrm{PCl}_{5}, \mathrm{SO}_{2}$$ and $$\mathrm{Cl}_{2}$$

Question 10 · difficulty L2 · understanding

Dinitrogen and dioxygen, the main constituents of air do not react with each other in atmosphere to form oxides of nitrogen because :

• A. $$\mathrm{N}_{2}$$ is unreactive in the condition of atmosphere.
• B. Oxides of nitrogen are unstable.
• C. Reaction between them can occur in the presence of a catalyst.
• D. The reaction is endothermic and require very high temperature.