Why is hydrochloric acid used in the laboratory in preference to nitric or sulfuric acids?

2 Answers
Nov 26, 2017

Because when it reacts rapidly with "Mg", it forms "H"_2 in the form of bubbles.

Explanation:

The chemical equation used in most cases to show formation of "H"_2 is:

"Mg"(s) + 2"HCl"(aq) -> "MgCl"_2(aq) + "H"_2(g)

The hydrogen can be detected either by observing the small "H"_2 bubbles in the solution or by holding a burning match or a lighter above the liquid container and watch the "H"_2 burn with a small 'boom' sound.

Nov 26, 2017

Why? Well probably for convenience....

Explanation:

HCl(aq) is available as the concentrated acid....[HCl]=10.6*mol*L^-1, so-called "muriatic acid", "spirits of salt"; bricklayers also use this stuff to wash the mortar off their brickwork.

We can conveniently add acid to water to dilute the concentrated acid (but never the reverse 'cos "if you spit in acid it spits back").

Both dilute and concentrated acids can be handled with appropriate care and precautions in the lab (which are?)...and the reaction with a metal generates dihydrogen gas....

Fe(s) + 2HCl(aq) rarr FeCl_2(aq) + H_2(g)uarr

On the other hand, "sulfuric acid" is a NON-OXIDIZING acid, and "nitric acid", the other common mineral acid, can generate poisonous and noxious NO_2 upon reduction.