question_answer

Hydrochloric acid is taken in a test tube and a piece of zinc metal is put into it. The collected gas evolved in the test tube is tested by bringing it near the burning matchstick.

(a) Which is the gas evolved in the test tube after the reaction?

(b) What happened to the burning matchstick when it is brought near to the mouth of the test tube.

Answer:

(a) The reaction takes place is

\[\begin{align}   & \operatorname{HCI}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,+\,\,\,\,Zn\,\,\,\,\,\xrightarrow{{}}\,\,\,\,ZnC{{I}_{2\,\,}}\,\,\,\,\,\,\,\,\,+\,\,\,\,{{H}_{2}}\uparrow  \\  & \operatorname{Hydrochloric}\,\,\,\,\,\,\,Zinc\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,Zinc\,Choride\,\,\,\,\,\,Hydrogen \\ \end{align}\]

The gas evolved is hydrogen gas\[{{\operatorname{H}}_{2}}\].

(b) As we know that \[{{\operatorname{H}}_{2}}\]is a combustible gas, so when the burning matchstick is brought near the mouth of the test tube containing hydrogen gas, it produces a pop up sound.