interesting brain teaser:P (1 Viewer)

[zeebobDD]

Find the ph of HCL 1x10^-8 mol/L, the answer is not 8. lol apparently it is 6.9 sumthin can anyone tell me how?

 

[Carrotsticks]

This is not really a brain teaser.

Generally, brain teasers can be done by anybody with no extra knowledge apart from common sense and basic logic.

 

[someth1ng]

I think you need add the concentration of water (1x10^-7) and the concentration of HCl (1x10^-8) to determine the net pH then use the pH formula to determine the actual pH.

 

[zeebobDD]

This is not really a brain teaser.

Generally, brain teasers can be done by anybody with no extra knowledge apart from common sense and basic logic.

well i did post it in the chemistry section, and you dont really have to be so technical about everything? who gives a shit what the title fkn says?

 

[rolpsy]

for very weak concentrations (~10^-6 M) the baseline concentration of H₃O⁺ ions in pure water becomes significant, and must be taken into account
use this formula,

[H₃O⁺] = C_a + K_w/[H₃O⁺]

where C_a is the concentration of the acid, and K_w is the dissociation constant of water

substituting, we get [H₃O⁺] = 1.05125×10^-7 mol/L
and so pH = 6.97829

see chapter 3.

 

[someth1ng]

for very weak concentrations (~10^-6 M) the baseline concentration of H₃O⁺ ions in pure water becomes significant, and must be taken into account
use this formula,

[H₃O⁺] = C_a + K_w/[H₃O⁺]

where C_a is the concentration of the acid, and K_w is the dissociation constant of water

substituting, we get [H₃O⁺] = 1.05125×10^-7 mol/L
and so pH = 6.97829

see chapter 3.

Can't you just do it:
[H+] in water=1x10^-7
[H+] provided by HCl=1x10^-8

Total [H+]=1.1x10^-7=6.96 or something like that?

 

[rolpsy]

Can't you just do it:
[H+] in water=1x10^-7
[H+] provided by HCl=1x10^-8

Total [H+]=1.1x10^-7=6.96 or something like that?

except some of the H⁺ ions provided by the HCl will react with OH^- ions to form water...

 

[someth1ng]

except some of the H⁺ ions provided by the HCl will react with OH^- ions to form water...

True but like, if it were in HSC - would you even be expected to do that?