A scientist dissolved a white powder in water and noted that the resulting solution was acidic. Why should the scientist not infer that the white powder contained hydrogen ions? (2 points) Acids never contain hydrogen ions. Bases always contain hydrogen ions. Some acids do not contain hydrogen ions. Acids only contain hydroxyl ions.

Respuesta :

Answer:

Some acids do not contain hydrogen

Explanation:

[prime examples are Lewis Acids]

There are 3 definitions of acid and bases. Arrhenius, bronsted and lewis acid bases. Among those Lewis acid are tricky because for them Some acids do not contain hydrogen. It's defintion of acid is something that accepts electrons (doesn't necessarily have to have hydrogen ions).

For example, From the Lewis theory, one can see that it is not necessary for an acid to have any protons, strictly speaking. The boron halides BF3, BCl3, BBr3, and BI3 are all Lewis acids and do not contain hydrogen. AlCl3 and AlBr3 are also common Lewis Acids used in Friedel-Crafts chemistry and do not contain hydrogen.

Finally, if we look at AlCl3 in water....From the reaction AlCl3 + 3H2O <=> Al(OH)3 + 3HCl,

HCl is a strong acid, so it will dissociate in water to form H+ and Cl-. As a result of this reaction, the solution will be acidic, with a pH < 7.

Therefore, the scientist cannot infer that white powder contained hydrogen atoms. It was the powder that reacted with water that led to formation of hydrogen ions, it wasn't necessarily present. Some common acids that have hydrogen ions are HCl, H2SO4 and such.

Answer:

Some acids do not contain hydrogen ions.

Explanation:

The more acidic a substance is (lower pH) the less hydrogen ions that substance has which can go as low as 1 x 10^0. Therefore, if a substance is very acidic, it has the possibility of not having hydrogen ions.