Question

Select the ion.

HCl
H2O
H3O+1

Answer 1

An ion must be charged either positively or negatively

A is incorrect - HCI is a formula that represents Hydrochloric Acid
B is incorrect - H20 is a formula that represents Water
C is correct - H3O+1 is a formula that represents Hydronium Ion; the ion is also positively charged

The answer is C.

Answer 2

Answer : The correct option is, $H_3O^+$

Explanation :

Ion : It is formed by the loss or gain of one or more electrons. It is an electrically charged atom or group of atoms.

Positive charged ion is formed by the loss of electrons and is known as cation and negative charged ion is formed by the gain of electrons and known as anion.

From the given options,

$HCl$ and $H_2O$ are the neutral molecules. while the $H_3O^+$ is a positive ion species that is cation because it has (+1) charge.

Hence, the correct option is, $H_3O^+$