Question

Which of the following has the highest concentration of H+ ions?

A. 0.001 M HCl
B. 0.01 M HCl
C. 10 M HCl
D. 0.1 M HCl

Answer 1

Answer : The correct option is, (C) 10 M HCl

Explanation :

When 1 mole of HCl dissociates then it gives 1 mole of hydrogen ion
`(H^+)` and 1 mole of chloride ion
`(Cl^-)`.

The balanced chemical reaction is,

`HCl\rightarrow H^++Cl^-`

(A) 0.001 M HCl

0.001 M concentration means, 0.001 moles present in 1 liter of solution.

When 0.001 M of HCl dissociates then it gives 0.001 of hydrogen ion
`(H^+)` and 0.001 M of chloride ion
`(Cl^-)`.

(B) 0.01 M HCl

0.01 M concentration means, 0.01 moles present in 1 liter of solution.

When 0.01 M of HCl dissociates then it gives 0.01 of hydrogen ion
`(H^+)` and 0.01 M of chloride ion
`(Cl^-)`.

(C) 10 M HCl

10 M concentration means, 10 moles present in 1 liter of solution.

When 10 M of HCl dissociates then it gives 10 of hydrogen ion
`(H^+)` and 10 M of chloride ion
`(Cl^-)`.

(D) 0.001 M HCl

0.1 M concentration means, 0.1 moles present in 1 liter of solution.

When 0.1 M of HCl dissociates then it gives 0.1 of hydrogen ion
`(H^+)` and 0.1 M of chloride ion
`(Cl^-)`.

From this we conclude that, 10 M HCl has the highest concentration of hydrogen ion
`(H^+)`.