Question

Choose the correct statements

• A. Solid N$_2$O$_5$ exists as NO$_2^+$NO$_3^-$ ion pair
• B. Nitrogen (IV) oxide disproportionates in basic aqueous medium
• C. Sodium nitrate and lead nitrate each on heating to 805°C decompose yielding NO$_2$ and O$_2$ gas
• D. Excess NH$_3$ reacts with NaOCl in dil. aqueous solution to produce N$_2$H$_4$

Answer 1

Answer: (A), (B), (D)

A, B, D

Answer 2

• Statement A: Solid N$_2$O$_5$ exists as an ionic compound, nitronium nitrate (NO$_2^+$NO$_3^-$), not as discrete molecular units.

• Statement B: Nitrogen(IV) oxide (NO$_2$) undergoes disproportionation in basic aqueous solution, forming nitrite (NO$_2^-$, N oxidation state +3) and nitrate (NO$_3^-$, N oxidation state +5) ions from an initial oxidation state of +4.

• Statement C: Sodium nitrate (NaNO$_3$) decomposes to sodium nitrite (NaNO$_2$) and oxygen (O$_2$), not NO$_2$. Lead nitrate (Pb(NO$_3$)$_2$) does decompose to PbO, NO$_2$, and O$_2$. Since the statement requires both to yield NO$_2$ and O$_2$, it is incorrect.

• Statement D: The Raschig process for hydrazine (N$_2$H$_4$) synthesis involves the reaction of ammonia (NH$_3$) with sodium hypochlorite (NaOCl). Excess NH$_3$ is used to prevent the further oxidation of N$_2$H$_4$ to N$_2$ by chloramine (NH$_2$Cl), which is an intermediate.