View Full Version : PH with the formula c=n/v
pop000
Jan 3, 2011, 07:07 AM
can you tell me if I correct I got question that says:find the pH of solution that it volume 50ml and it made by dissolved 0.012gr LiOH. I found that v=0.05L n=0.0005mol,C=0.01
I am not sure if the pH is 13 or 10.
someone can help me to find the pH ?
if I found the c,n,v of the formula is correct that the concentration of hydroxide ions is 10^-1?
thanks.
pop000
Jan 3, 2011, 07:31 AM
sorry here I mean "if i found the c,n,v of the formula is correct that the concentration of hydroxide ions is 10^-1?" not 10^-1 but 10^-2
Dr.Jim
Jan 4, 2011, 03:25 AM
pH=-log(H+) (base 10 log)
pOH = -log(OH-)
pH + pOH = 14.00
Find the concentration of LiOH in moles/liter. Since LiOH is a strong base, this also will be the concentration of OH-. Find the pOH using the above formula. Subtract that answer from 14.00 to get the pH. Remember, also look at your answer and ask yourself if it makes sense. Your answer should be above 7.00, since LiOH is a base.
Dr.Jim
pop000
Jan 4, 2011, 03:56 AM
well so pOH = -log(OH-)=10^-2=2
and if I use the formula pH + pOH = 14.00 so I know that the pH here is 12 and is makes sense, because we speak abut strong base.