Question

A metal nitrate 'A' on heating gives a metal oxide along with evolution of a brown coloured gas 'B' and a colourless gas, which helps in burning. Aqueous solution of 'A' when reacted with potassium iodide forms a yellow precipitate.

1. Identify 'A' and 'B'
2. Name the types of the reactions involved in the above statement.

Answer 1

The metal in compound A is lead (Pb).

Therefore, we can write

Reaction 1 as

\[\ce{2Pb(NO_3)_2->[\Delta] 2PbO + 4NO_2 + O_2}\]

Reaction 2:

\[\ce{Pb(NO_3)_2 + 2KI ->Pbl_2 + 2KNO_3}\]

Compound A - lead nitrate: \[\ce{Pb(NO_3)_2}\]

Compound B - nitrogen dioxide- NO₂

Reaction 1 is thermal decomposition, whereas,

reaction 2 is double decomposition reaction.