29 Replies
@Dexter
Note for OP
+solved @user1 @user2... to close the thread when your doubt is solved. Mention the users who helped you solve the doubt. This will be added to their stats.ill take the 61st one
HBr is a strong acid
it fully dissociates
all of HBr becomes ions
i mean i have in both 60th and 61 but yh
HBr ---> H(+) + Br(-)
so the concentration of H(+)
is equal to the concentration of HBr
thats the assumption of strong acids
that the reaction goes all the way through
antilog of 4.25?
minus of antilog right?
but yes
yh yh minus
try doing the others with the same logic
nitric acid, HNO3, is also strong
let me try
once
There's a variation as well
First you solve these then we can talk about that
if i am not doing any blunder again the ph of HNO3 should be 1.7 in 60th a
tell tell
crazy stuff im getting -0.6 as ph in b part
Calculate the ph of 10^-7 M HCl 🥸
And tell me what it turns out to be
Uhh weird I'll see ruko
wait wht
it is 7 isnt it?
howw
hcl being neutral
It's not 7
Acid hai
Acidic to karega
You remember we are missing something?
wait do we need to consider the autoionisation of water also?
EXACTLY!!
paani?
That will give you a value of some 6.84 or 6.92 whatever but it would be less than 7
Haanji:)
ok woah but one question tht i have had in autoionization of water is mujhe kaise pta chlega kis extent tak paani ionize hoga?
tht is almost neutral though very veryy less acidic
See paani har baar bohot Kam ionise hota hai isiliye we neglect that effect
So when our values contradict facts
Like acid hai par ph neutral
Base hai par ph neutral
Then we gotta consider that as well kyunki us negligible effect se hi acidity/basicity aa rahi hai
Yeah it sure is
But it's not 7
okk but in calc hum agr consideration me le rhe say in this example of hcl tht u gave so much should i take the value of H+ from water how do i get that value
yh i hve realised neglecting some values are very imp otherwise it drives u nuts
Write the expression of ka and H+ concentration as you did for the others
Just consider the contribution of water as well
yh tht i got but what value to take of for the ions of h+ from h20, how do i get tht ?
tht is what i dont understand
They give 10^-7 right?
Water molecules
we going to take this only all the time? wont it chnge?
Yes at 25°C utna hi karta hai water
H+ concentration becomes 10^-7 plus 10^-7
pH = -log(2×10^-7)
That thing I just checked online....turns out to be 6.79 apparently
okk got it thnkss
+solved @Nimboi @Varun_Arora
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