# Homework Help: CHEM QUESTION - answer fast thx alot

1. Jan 9, 2005

### xLaser

:::::: CHEM QUESTION - answer fast plz thx alot ::::::::

Hi, this maybe a very stupid question but I have a test coming up tomorrow and i'm not sure of this thing here:

Suppose you were given 1 M hydrochloric acid (I assume 1 M to mean a concentration of 1 mol/ L ) Calculate its [H3O]+ (square brackets mean concentratioN) and pH.

ok what did was using pH = - log [H3O]+

then u get -log (1) = 0

there pH =0 , which makes sense since HCl is a very strong acid.

and then apparently the [H3O]+ is 1 mol/L since it was given in the question.

BUT THEN IF IT LIKE THIS, THEN WHAT KIND OF STUPID QUESTION IS THIS???? LOL!

I doubt i did this right so can someone please confirm that i did it right or wrong? thanks.

2. Jan 9, 2005

### Pyrrhus

A strong acid diassociates completely in $H_{3}O^{+}$ or $H^{+}$ so yes the ph will be -log[concentration] and the amount of $H_{3}O^{+}$ or $H^{+}$ will be the HCL concentration.