When a sample of `KNO_(3)` is subjected to heating, the volume of oxygen liberated was sufficient for the combustion of one mole of ethylene. For giving same amount of oxygen, what is the amount of lead nitrate required ot be decomposed? Also, find out the volume occupied by the gaseous products at STP during this decomposition.

Explanation

`2KNO_(3) to 2KNO_(2) + O_(2)`
1 mole of ethylene requires 3 moles of oxygen
`2Pb(NO_(3))_(2) to 2PbO + 4 NO_(2) + O_(2)`
6 moles of `Pb(NO_(3))_(2) ` is required to given 3 moles of oxygen
`:.` Weight of `Pb(NO_(3))_(2) = 6 xx 330 = 1980` g
Volume occupied by gaseous `(NO_(2) and O_(2))` products
` = 15 xx 22.4 " L at STP " = 336` L