Question

Which 1.0 M solution has the lowest pH?
 A -HCN
 B -H3PO4
 C -H2C2O4
 D -HCl

Answer 1

Answer:The correct answer is option D.

Step-by-step explanation:

Out of these four acids the strongest acid is hydrochloric acid which completely dissociates inits aqueous solution.Where as other acids are weak acid do not dissociates complete in their aqueous solution.

`HCl(aq)\rightarrow H^+(aq)+Cl^-(aq)`

0.1 M of HCl will form 0.1 M of
`H^+` ions.

The pH is given as:

`pH=-\log[H^+]=-\log[0.1]=1`

Hence,the correct answer is option D.

Answer 2

The solution with the lowest pH would mean that it is an acid, specifically a strong acid which completely dissociates into ions in aqueous solution. Among the choices listed above, I think the correct answer is option D. It is nitric acid that will have the lowest pH because it is the only strong acid in the group