Question

Zinc produce gas X on reaction with sulphuric acid :
A.Name the gas X .
B.Write the equation of the reaction .
C.How will you identify gas X ?

Answer 1

Hint: When we dissolve a pure metal in a non oxidizing agent like sulphuric acid a high purity salt is produced . Zinc being most electronegative than hydrogen replaces ${H^ + }$ ion in sulphuric acid and a displacement reaction takes place .

Complete step by step answer:
A single displacement reaction takes place when zinc is dissolved in sulphuric acid because zinc being more electronegative than hydrogen replaces it in sulphuric acid . The reaction is as follows :
$Zn + {H_2}S{O_4}\xrightarrow{{}}ZnS{O_4} + {H_2}$
In this reaction we saw that oxidation of zinc and reduction of hydrogen ion took place .
Zinc is oxidized as $Zn\xrightarrow{{}}Z{n^{ + 2}} + 2{e^ - }$
And hydrogen ion is reduced as $2{H^ + } + 2{e^ - }\xrightarrow{{}}{H_2}$
Overall reaction is as follows : $Zn + 2{H^ + }\xrightarrow{{}}Z{n^{2 + }} + {H_2}$
When zinc is dissolved in the sulphuric acid an effervescence comes out from the reaction mixture . By observing the colour of gas liberated and by smelling the gas we can easily predict that it is hydrogen gas.
This reaction is an exothermic reaction because energy is released during this reaction .
Now we can answer all of the above question :
A.The gas X is hydrogen gas $\left( {{H_2}} \right)$
B.Equation of the reaction is $Zn + {H_2}S{O_4}\xrightarrow{{}}ZnS{O_4} + {H_2}$
C.When zinc is dissolved in sulphuric acid a colourless , odourless and tasteless gas is liberated which shows that the gas is hydrogen .


Note:
The hydrogen gas evolved during the reaction is colourless , odourless and tasteless which makes it difficult to detect . It is a non poisonous gas and it is chemically inert at room temperature .