Question

$2Al\left(s\right)+6HCl\left(aq\right)\to 2{Al}^{3+}\left(aq\right)+6{Cl}^{-}\left(aq\right)+3H_2\left(g\right)$
Which of the following is correct about the above reaction?

• A. Precipitation reaction
• B. Acid/base reaction
• C. Redox reaction
• D. Combustion reaction
• E. Decomposition reaction

Answer 1

Answer: (C)

Redox reaction

$2Al+6HCl\to 2A{l}^3++6C{l}^{-}+3H_2$
here, $Al$ is oxidised to $A{l}^{3+}$ and $H^{+}$ ( in $HCl$) is reduced to $H^0$ ( in $H_2$)
Redox is a contraction of the name for a chemical reduction–oxidation reaction. Any such reaction involves both a reduction process and a complementary oxidation process. Redox reactions include all chemical reactions in which atoms have their oxidation state changed; in general, redox reactions involve the transfer of electrons between chemical species. The chemical species from which the electron is stripped is said to have been oxidized, while the chemical species to which the electron is added is said to have been reduced. Oxygen is not necessarily included in such reactions as other chemical species can serve the same function.
The term "redox" comes from two concepts involved with electron transfer: reduction and oxidation.[1] It can be explained in simple terms:
Oxidation is the loss of electrons or an increase in oxidation state by a molecule, atom, or ion.
The reduction is the gain of electrons or a decrease in oxidation state by a molecule, atom, or ion.