Nitrogen dioxide and sulphur dioxide have some properties in common. Which property is shown by one of these compounds, but not by the other?
- Is soluble in water.
- Is used as a food preservative.
- Forms 'acid-rain'.
- Is a reducing agent.
Answer
(2) Is used as a food preservative.
Solution
Both NO2 and SO2 are acidic oxides, soluble in water:
2NO2 + H2O HNO3 + HNO2; SO2 + H2O H2SO3
⇒ both form acid rain.
Both can act as reducing agents (N in NO2 is +4 and can go to +5; S in SO2 is +4 and can go to +6).
As per NCERT, SO2 is used as an anti-chlor, disinfectant and preservative; NO2 is not used as a food preservative.
Answer: (2)