Heating of a mixture consisting of potassiumm nitrate , carbon and sulphur involves which of the following chemical changes ?

Options

A. decomposition and combination
B. double decomposition
C. combination and displacement
D. displacement and decomposition

Answer

a

Explanation

Gunpowder is a mixture of `KNO_3`, sulphur and coke. When it is heated, `KNO_3` undergoes decomposition to produce `O_2` and `KNO_2`. S and C burn in the presence of `O_2` producing `SO_2` and `CO_2`.
`2KNO_3 overset(Delta)to2KNO_2 + O_2`
`S + O_2 to SO_2`
`C + O_2 to CO_2`
Hence, the type of chemical changes involved is decomposition and combination.