Question

Name a substance which, on heating, leaves behind no residue.
(A)Methane gas
(B)Ammonium nitrate
(C)Camphor
(D)All of the above

Answer 1

Hint: Substances which burn easily or are inflammable , mostly leave no residue on heating, some of them are used on daily purpose by us, and rest are seen in our close surroundings.

Complete answer:
To know which option will leave no residue on heating, we will consider reaction one by one of the following given options.
Heating of methane gas gives carbon dioxide and water.
     \[C{{H}_{4}}+2{{O}_{2}}\to C{{O}_{2}}+{{H}_{2}}O\]
Carbon dioxide is a gas and water escapes as vapours, therefore, methane gas leaves no residue after heating.
Since we have all of the above options also given to us in the question , we will move to other options for seeing the heating reaction given by the rest of the two substances.
Ammonium Nitrate,on heating it gives, nitrous oxide and water vapour.
     \[N{{H}_{4}}N{{O}_{3}}\to {{N}_{2}}O+2{{H}_{2}}O\]
Ammonium nitrate is a salt which on heating leaves no residue. Heating of ammonium nitrate is very explosive, we get the smell of sweet smelling nitrous gas.
Camphor is a very well known substance, which is known to sublimate on heating. When camphor is heated, it changes directly from solid state to gaseous state, without changing into liquid state. It leaves no residue after heating.
\[2{{C}_{10}}{{H}_{16}}O+27{{O}_{2}}\to 20C{{O}_{2}}+16{{H}_{2}}O\]
Therefore, all the three options given in the questions, when heated, leave no residue.

So (D) option is the correct answer. All of the above leaves no residue on heating

Note: Ammonium nitrate explodes at temperature above ${{210}^{\circ }}C$. Methane gas is produced by cow dung cakes, which is used as fuel in rural areas. Sometimes, we may observe some black depositions g after burning of the above substances, that may be present due to the presence of impurities.