Question

Complete the reaction $Zn + {H_2}S{O_4} = ?$

Answer 1

Hint : Zn is the symbol for Zinc metal which is an element of group 12 of the d-block elements. ${H_2}S{O_4}$ is the formula for sulphuric acid (which is considered as a strong acid). So, the above given reaction is a reaction of an acid with a metal and the products formed will be a salt and evolution of hydrogen gas $({H_2})$ .

Complete Step By Step Answer:
The given equation is:-
$Zn + {H_2}S{O_4} = ?$
Zinc metal which is represented by ‘Zn’ is an element of group 12 of the d-block elements while ${H_2}S{O_4}$ is the formula for sulphuric acid.
So, the reaction between the zinc metal and sulphuric acid is a type of single displacement reaction. In this type of reaction a stronger (more reactive on the basis of reactivity series) metal or element displaces other elements from it’s compound.
Reactivity of elements is given by reactivity series in which the order of reactivity of metals in decreasing order is as follows:-
$K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Hg > Ag > Au$
Therefore, from the above reactivity series, we can clearly see that Zinc metal is much more reactive than Hydrogen, so it can easily displace hydrogen from ${H_2}S{O_4}$ an forms a salt with the formula $ZnS{O_4}$ and Hydrogen displaced will be released (evolved) in the form of hydrogen gas $({H_2})$ .
So, it can be concluded that when a metal reacts with an acid, two products will be formed which are salt and hydrogen gas $({H_2})$ .
Therefore, the complete reaction will be as follows:-
$Zn + {H_2}S{O_4} \to ZnS{O_4} + {H_2}$
This reaction is widely used in the laboratories to produce hydrogen gas.

Note :
It can be concluded that the reaction between a metal and an acid produces a salt and hydrogen gas. Hydrogen gas evolved can be tested by bringing a burning candle near the gas bubbles and they will burn with a pop sound. Only hydrogen gas burns with a pop sound, so we can say that the gas produced is hydrogen gas.