Question

A colourless and odourless gas P is evolved during thermal decomposition of lead nitrate. P reacts with the main component of biogas to form compounds Q and R. P, Q and R respectively are

Answer 1

Here P is O2, because it is that colourless and odourless gas which evolve during the decomposition of Pb(NO3)2. And when oxygen reacts with CH4 it form CO2 and H2O as oxidation took place.

Thus

P- O2

Q-CO2

R-H2O

Answer 2

Answer: The compound P is oxygen gas, compound Q is carbon dioxide gas and compound R is water.

Explanation:

We are given a chemical compound having formula $Pb(NO_3)_2$

The chemical equation for the decomposition of lead nitrate follows:

$2Pb(NO_3)_2(s)\rightarrow 2PbO(s)+O_2(g)+4NO_2(g)$

The gases released are oxygen gas and nitrogen dioxide gas. Oxygen gas is a colorless, odorless gas and nitrogen dioxide is a reddish-brown colored gas.

The main component of biogas is methane.

When oxygen gas reacts with methane, it leads to the formation of carbon dioxide and water molecule. This reaction is known as combustion reaction.

The chemical equation for the combustion of methane follows:

$CH_4+2O_2\rightarrow CO_2+2H_2O$

Hence, the compound P is oxygen gas, compound Q is carbon dioxide gas and compound R is water.