Chemistry - Complete P-block Question with Solution | TestHub

When Zn reacts with very dilute HNO₃, it produces N₂O (nitrous oxide) or NH₄NO₃ (ammonium nitrate), not a gaseous product. With NaOH, H₂ is produced. With H₂SO₄, H₂ is produced. With concentrated HNO₃, NO₂ is produced. Therefore, very dilute HNO₃ is the correct answer.

Explanation:

1. Reaction with NaOH: $2\mathrm{Zn}+2\mathrm{NaOH}+2{\mathrm{H}}_2\mathrm{O}\to \mathrm{N}{\mathrm{a}}_2[\mathrm{Zn}(\mathrm{OH}{)}_4]+{\mathrm{H}}_2$ (produces H₂ gas)

2. Reaction with Dil. H₂SO₄: $\mathrm{Zn}+{\mathrm{H}}_2\mathrm{S}{\mathrm{O}}_4\to \mathrm{ZnS}{\mathrm{O}}_4+{\mathrm{H}}_2$ (produces H₂ gas)

3. Reaction with V. dil. HNO₃: $4\mathrm{Zn}+10\mathrm{HN}{\mathrm{O}}_3(verydilute)\to 4\mathrm{Zn}(\mathrm{N}{\mathrm{O}}_3{)}_2+{\mathrm{N}}_2\mathrm{O}+5{\mathrm{H}}_2\mathrm{O}$ (produces N₂O gas) or $4\mathrm{Zn}+10\mathrm{HN}{\mathrm{O}}_3(verydilute)\to 4\mathrm{Zn}(\mathrm{N}{\mathrm{O}}_3{)}_2+\mathrm{N}{\mathrm{H}}_4\mathrm{N}{\mathrm{O}}_3+3{\mathrm{H}}_2\mathrm{O}$ (produces no gas)

4. Reaction with Conc. HNO₃: $\mathrm{Zn}+4\mathrm{HN}{\mathrm{O}}_3(conc.)\to \mathrm{Zn}(\mathrm{N}{\mathrm{O}}_3{)}_2+2\mathrm{N}{\mathrm{O}}_2+2{\mathrm{H}}_2\mathrm{O}$ (produces NO₂ gas)

The question states "no gases product". While very dilute HNO₃ can produce N₂O, it can also produce NH₄NO₃, which is not a gas. Among the given options, very dilute HNO₃ is the only one that can result in no gaseous product, depending on the specific conditions and concentration. However, the common understanding in such questions is that very dilute HNO₃ is the reducing agent that produces ammonium nitrate, which is not a gas.

Therefore, the reaction of Zn with very dilute HNO₃ can yield ammonium nitrate, which is not a gaseous product.