Question

Hydrogen from HCl can be prepared by:
A. $Mg$
B. $Cu$
C. $P$
D. $Pt$

Answer 1

As we know that the hydrogen chemical symbol is $H$ and its atomic number is $1$. In the family of chemical elements, hydrogen is the simplest member. It is a flammable gaseous substance. Hydrogen is tasteless, odourless, colourless. In the universe, hydrogen is the most abundant element. Hydrogen has many uses.

Complete step by step answer:
We have to remember that the hydrochloric acid (IUPAC name – chlorane, common name – muriatic acid) formula is $HCl$, it is an acid. Hydrochloric acid consists of hydrogen chloride and water, and a variety of other chemical species also (such as hydronium ion and chlorine ions).
Hydrochloric acid is prepared by,
$HCl + {H_2}O \to {H_3}{O^ + } + C{l^ - }$
Although it may seem easy to, the speciation of hydrochloric acid is more complicated.
Alkali metals and alkaline earth metals (collectively known as $s -$block elements) release hydrogens when reacting with acids and displace hydrogen from dilute acids if electrons are supplied to ${H^ + }$ ions of the acid.
As we know that the alkali metals (Group $1$ elements) – Lithium atomic number $3$, Sodium atomic number $11$, potassium atomic number $19$, rubidium atomic number $37$, caesium atomic number $55$ and francium atomic number $87$.
We have to remember that the alkaline earth metals (Group $2$ elements) are Beryllium (at. No. $4$), magnesium (at. No. $12$), calcium (at. No. $20$), strontium (at. No. $38$), barium (at. No. $56$), and radium (at. No. $88$).
In the above elements, radium is a radioactivity element. Its characteristics are not well-established.
Among the given options magnesium ($Mg$) is the only element which belongs to alkaline earth metal. Copper $(Cu)$and platinum $(Pt)$are $d -$block elements. And Phosphorus$(P)$, phosphorus trichloride reacts with $HCl$. So, magnesium releases hydrogen from hydrochloric acid. The chemical equation is,
$Mg + 2HCl \to MgC{l_2} + {H_2}$
The correct option is B. $Mg$.

Note:
We have to remember that the hydrogen chloride (IUPAC name and common also same) chemical formula also $HCl$, this is colourless gas at room temperature. But Hydrochloric acid is an acidic solution. Hydrochloric acid is an important reagent in chemical laboratories and in industrial processes it is used as refining metal. Hydrochloric acid dissolves noble gases. Hydrochloric acid is used for preparation of aqua regia, chlorine and other chloride compounds.