- thermal decomposition of lead nitrate which produces brown fumes of nitrogen dioxide.
- thermal decomposition of lead nitrate which produces brown fumes of lead oxide.
- oxidation of lead nitrate forming lead oxide and nitrogen dioxide.
- oxidation of lead nitrate forming lead oxide and oxygen.
Here is the Explanation:
The correct option is (a) thermal decomposition of lead nitrate which produces brown fumes of nitrogen dioxide.
When lead nitrate (Pb(NO₃)₂) is heated, it decomposes into lead oxide (PbO), nitrogen dioxide (NO₂) and oxygen (O₂). The nitrogen dioxide gas is what gives the brown fumes their color. The chemical equation for this reaction is:
2Pb(NO₃)₂ (s) → 2PbO (s) + 4NO₂ (g) + O₂ (g)
The other options are incorrect because:
- (b) thermal decomposition of lead nitrate which produces brown fumes of lead oxide: Lead oxide is a yellow solid, not brown fumes.
- (c) oxidation of lead nitrate forming lead oxide and nitrogen dioxide: Lead nitrate is already an oxidized compound, so it cannot be further oxidized.
- (d) oxidation of lead nitrate forming lead oxide and oxygen: This reaction does not produce nitrogen dioxide, which is the gas that gives the brown fumes their color.
It is important to note that this experiment should only be conducted under the supervision of a qualified teacher or chemist, as lead nitrate is a toxic substance and nitrogen dioxide gas can be harmful if inhaled.
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