What is the concentration of HCl if its pH is 3?

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Answer 1 · 2018-04-29T21:17:45

#10^(-3) " M"#

To find the concentration of something that dissociates into #H^+# and something else from the pH, we use the formula:

#10^(-pH)#

So this becomes:

#10^(-3) " M"# #quad#(M stands for molar)

Answer 2 · 2018-04-30T01:12:24

#10^-3 \ "M"=0.001 \ "M"#

The #"pH"# of an aqueous solution is given by the equation,

#"pH"=-log[H^+]#

#[H^+]# is the hydrogen ion concentration in terms of molarity

The dissociation equation for hydrochloric acid is:

#HCl(aq)->H^+(aq)+Cl^(-)(aq)#

So, one mole of hydrochloric acid contains one mole of hydrogen ions.

Therefore, the hydrogen ion concentration will be,

#3=-log[H^+]#

#[H^+]=10^-3 \ "M"#

#=0.001 \ "M"#