NEET Practice Questions (MCQs) with Answers & Solutions

The boiling point of hydrides generally increases as we move down the group in the periodic table due to an increase in molecular weight. However, $H_2O$ has an exceptionally high boiling point due to hydrogen bonding. Among $H_2S$, $H_2Se$, and $H_2Te$, $H_2S$ has the lowest molecular weight, and hence, the lowest boiling point.

$V_2O_5$ acts as a catalyst in the Contact Process for the production of sulfuric acid. The specific reaction where $V_2O_5$ is used is the conversion of $SO_2$ to $SO_3$: $$2SO_2 + O_2 \rightarrow 2SO_3$$ This is a crucial step before $SO_3$ can be hydrated to form $H_2SO_4$.

Ozone reacts with trimethyl paper and turns it violet. This is a standard test for the presence of ozone.

The molecular formula for sulphur is typically $S_8$, indicating that there are 8 atoms in one molecule of sulphur.

The bond angle decreases as we move down the group in the periodic table due to increasing atomic size and decreasing bond pair-bond pair repulsion. Thus, the bond angle is minimum for $ H_2 Te $.

In the reaction $ SO_2 + 2H_2S ightarrow 3S + 2H_2O $, sulphur dioxide ( $ SO_2 $ ) acts as an oxidizing agent. It oxidizes $ H_2S $ to sulfur (S), and in the process, $ SO_2 $ itself gets reduced to $ H_2O $. Hence, $ SO_2 $ is the oxidizing agent in this reaction.

When $ SO_2 $ is passed through cupric chloride ( $ CuCl_2 $ ) solution, a white precipitate of $ Cu_2Cl_2 $ is formed, and the solution becomes colorless. The reaction is: $$ SO_2 + 2CuCl_2 + 2H_2O ightarrow Cu_2Cl_2 + 2HCl + H_2SO_4 $$. Here, $ SO_2 $ reduces $ CuCl_2 $ to $ Cu_2Cl_2 $, resulting in the formation of a white precipitate and a colorless solution.

Among the given options, $ SO_3 $ (sulfur trioxide) is acidic. When $ SO_3 $ is dissolved in water, it forms sulfuric acid ( $ H_2SO_4 $ ), which is a strong acid: $$ SO_3 + H_2O ightarrow H_2SO_4 $$. The other options ($ N_2O $, $ BeO $, and $ HgO $) are either neutral or basic oxides.

Sulphur - (1) monoclinic (2) Rhombic (3) Plastic